One of the most promising probes to study deconfined matter created in high energy nuclear collisions is the energy loss of (heavy) quarks. It has been shown in experiments at the Relativistic Heavy Ion Collider that even charm and bottom quarks, despite their high mass, experience a remarkable medium suppression in the ...
NASA Astrophysics Data System (ADS)
High transverse momentum single (non-photonic) electrons are shown to be sensitive to the stopping power of both bottom, b, and charm, c, quarks in AA collisions. We apply the DGLV theory of radiative energy loss to predict c and b quark jet quenching and compare the FONLL and PYTHIA heavy flavor fragmentation and decay schemes. We ...
DOE Information Bridge
Thermalization and collective flow of charm (c) and bottom (b) quarks in ultrarelativistic heavy-ion collisions are evaluated based on elastic parton rescattering in an expanding quark-gluon plasma (QGP). We show that resonant interactions in a strongly interacting QGP (sQGP), as well as parton coalescence, can play an essential role ...
E-print Network
The presentations at the Fifth Moriond Workshop on Heavy Quarks, Flavor Mixing, and CP Violation (La Plagne, France, January 13-19, 1985) are summarized. The following topics are reviewed. What's New (beyond the top, top quarks, bottom quarks, charm quark...
National Technical Information Service (NTIS)
PubMed
We report on the searches for the production of scalar top quarks and scalar bottom quarks using data taken during Run II of the Fermilab Tevatron colliders in pp-bar collisions at a center of mass energy of 1.96 TeV. We find our data to be consistent with the Standard Model expectations and derive 95% confidence level limits on the ...
Energy Citations Database
We evaluate heavy-quark (HQ) transport properties in a quark-gluon plasma (QGP) within a Brueckner many-body scheme employing interaction potentials extracted from thermal lattice QCD. The in-medium T matrices for elastic charm- and bottom-quark scattering off light quarks in the QGP are dominated by attractive ...
Bottom Quark. 4.2 GeV. Found. Tauon. 1.8 GeV. Found. Charm Quark ... Problem 2 - A proton consists of two Up Quarks and one Down Quark held tightly together ...
NASA Website
The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in ex...
Heavy quarks, charm and bottom, are believed to be produced mostly via initial gluon fusion in nuclear collisions at RHIC. Heavy quark propagation through the hot and dense medium created in heavy ion collisions probes the properties of the medium. Recently a large suppression of non-photonic electrons up to a pT of 10 GeV/c from ...
The theory of heavy quark production in hadronic reactions is reviewed. Rates for the production of charm, bottom and top quarks at energies of current interest are presented. 34 refs., 19 figs., 2 tabs.
the mass and lifetime of the Omega-sub-b (Ωb), a particle that contains two strange quarks and a bottom quark. The short-lived particle is an exotic relative of the much more...
Science.gov Websites
Transverse momentum (p{sup e}{sub T}) distribution of electrons for 0.3 < p{sup e}{sub T} < 9.0 GeV/c has been measured in midrapidity (|{eta}| < 0.35) in Au+Au collisions and p+p collisions at {radical}s{sub NN} = 200 GeV by the RHIC-PHENIX experiment. Two methods for background subtraction were applied to determine the electron yield from open charm and ...
A surprising discovery at RHIC is the large suppression of heavy quarks in heavy ion collisions. Perturbative QCD predicted much less suppression for heavy mesons than 0? mesons, however the measured suppression of charm and bottom quarks traversing Quark-Gluon Plasma from measurements is significantly larger than ...
RHIC-PHENIX has observed a large suppression pattern and azimuthal anisotropy of non-photonic electron at mid-rapidity (|{eta}|< 0.35) in Au+Au collisions at {radical}s{sub NN} = 200 GeV. To understand these results and the interaction of heavy quarks in the hot and dense medium, experimental determination of production ratio of charm over ...
Due to their large masses, heavy flavor quarks (charm and bottom) are believed to be unique probes to the strongly-coupled QCD matter created in high energy Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). When heavy flavor quarks travel through the QCD medium, they are expected to lose less energy ...
Expectations for the momentum distribution of nonperturbative charm and bottom quarks in the proton are derived from a variety of models for the Fock space wave function on the light cone.
In weak interaction models with two charged W bosons of comparable mass, there exists a novel possibility for the weak interactions of the bottom quark, in which the (anti u b)R current occurs with maximal strength. It is noted that multimuon production i...
The analytic expressions for the production cross sections of polarized bottom and top quarks in e(+)e(-) annihilation are explicitly derived at the one-loop order of strong interactions. Chirality-violating mass effects will reduce the longitudinal spin ...
I investigate bottom-quark fragmentation in H {yields} bb-bar processes. I discuss the implementation of collinear and soft resummation, in the next-to-leading logarithmic approximation, and the inclusion of non-perturbative contributions taken from LEP and SLD data.
The production of bottom quarks at the SSC and the formalism and phenomenology of observing CP violation in B meson decays is discussed. The production of a heavy t quark which decays into a real W boson, and what we might learn from its decays is examined.
The production of bottom quarks at the SSC and the formalism and phenomenology of observing CP violation in B meson decays is discussed. The production of a heavy t quark which decays into a real W boson, and what we might learn from its decays is examine...
We present predictions for the rapidity and transverse momentum distributions for inclusive production of bottom quarks at SSC energies, pp -> bX. Our computations are based on the simplest, lowest-order QCD mechanisms. To estimate uncertainties, we use t...
A summary is presented of theoretical expectations for the total cross sections for bottom quark production, for longitudinal and transverse momentum distributions, and for b, /bar b/ momentum correlations at Fermilab fixed target and collider energies.
We report on heavy quark mass calculations using Fermilab heavy quarks. Lattice calculations of heavy-strange meson masses are combined with one-loop (automated) lattice perturbation theory to arrive at the quark mass. Mesons are constructed from Fermilab heavy quarks and staggered light ...
The quantum chromodynamics (QCD) radiative corrections to charged current heavy quark production are given in the limit that the weak partner is massless, i.e. using a bottom structure function for top quark production. The results for charm production in...
Recent results in heavy quark physics from the D0 experiment at the Fermilab Tevatron Collider are reported. Topics included are top quark production and mass determination, bottom production and correlations, and charmonium production. 20 refs., 10 figs., 2 tabs.
I discuss some aspects of the comparison between QCD predictions and experimental data in charm and bottom production.
For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the classical model agrees with the lifetime from quantum mechanics to good ...
Measurements of heavy quarks (charm and bottom) produced in relativistic collisions of heavy ions have provided significant insight into the dynamics of the dense partonic matter created at RHIC. The PHENIX detector is well suited to make measurements of these quarks through their semi-leptonic decay channels. By subtracting a cocktail ...
Parity violation induced by the chromo-anapole form factor of the bottom quark, generated from weak corrections, is studied in polarized hadron collisions. The forward-backward asymmetry in the bottom quark pair production at polarized pp and p{anti p} colliders is evaluated in the Standard Model and in a Two Higgs ...
We searched for scalar bottom quarks 156 pb(-1) of pp collisions at radicalS = 1.96 recorded by the Collider Detector at Fermilab II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in -parity conserving models of supersymmetry when the mass of the gluino exceeds that of the ...
We searched for scalar bottom quarks in 156 pb{sup -1} of {bar p}p collisions at {radical}s = 1.96 TeV recorded by the CDF II experiment at the Tevatron. Scalar bottom quarks can be produced from gluino decays in R-parity conserving models of supersymmetry when the mass of the gluino exceeds that of the scalar ...
We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) ...
Using new four-loop results for the heavy quark vacuum polarization and new data for bottom quark production in electron-positron annihilation, an update on the determination of charm- and bottom-quark masses through sum rules has been performed. The previous result for the charm-quark mass, ...
We compute, for the first time, the absorptive part of the massless correlator of two quark scalar currents in five loops. As physical applications, we consider the [symbol: see text](alpha(s)4) corrections to the decay rate of the standard model Higgs boson into quarks, as well as the constraints on the strange quark mass following ...
We compute, for the first time, the absorptive part of the massless correlator of two quark scalar currents in five loops. As physical applications, we consider the O({alpha}{sub s}{sup 4}) corrections to the decay rate of the standard model Higgs boson into quarks, as well as the constraints on the strange quark mass following from ...
An updated heavy quark-antiquark potential is constructed by matching the short-distance perturbative part to long-distance lattice QCD results at an intermediate r scale. The static potential and the order 1/m potential are both analyzed in this way. Effects of order 1/m in charmonium and bottomonium spectra are discussed in comparison. Charm and bottom ...
Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it...
The axial vector isosinglet neutral current induced by the QCD correction through the triangle diagram of the quarks is studied. The large mass difference between the top quark and the bottom quark gives a considerable amount of the correction to the axial part of the Z couplings to the quarks. ...
Higgs-boson production in association with bottom quarks, pp/pp{yields}bbH+X, is one of the most important discovery channels for supersymmetric Higgs particles at the Tevatron and the LHC. We have calculated the next-to-leading-order QCD corrections to the parton processes qq,gg{yields}bbH and present results for total cross sections and for distributions ...
The magnetic moments of ground state single, double and triple heavy baryons containing charm or bottom quarks are calculated in a relativistic three-quark model, which, in the heavy-quark limit, is consistent with heavy-quark effective theory and heavy hadron chiral perturbation theory. The ...
We present a model independent analysis of bottom quark weak interactions. In particular, we show how a study of multi-lepton events in e exp + e exp - annihilation can provide evidence for bottom particle production, and determine all the parameters of t...
Several developments affecting the possibility of Higgs detection are discussed. These include the level of certainty about the t quark mass, Monte Carlo programs to generate both signal and background events, and separation and/or enhancement of heavy quark jets from jets due to light quarks or gluons, and the possibility that the ...
One of the main challenges of the Tevatron at Fermilab and the Large Hadron Collider (LHC) at CERN is the determination of standard model parameters at the TeV scale. In this context various processes will be investigated which involve bottom-quark jets in the final state, for example, decays of top-quarks or gauge bosons of the weak interaction. Hence the ...
We present a complete next-to-leading order calculation for the total cross section for inclusive Higgs pair production via bottom-quark fusion at the CERN Large Hadron Collider in the minimal supersymmetric standard model and the minimal supergravity model. We emphasize the contributions of s quark and gluino loops and the decoupling properties of our ...
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3<9GeV/c at midrapidity (|y|<0.35) from heavy-flavor (charm and bottom) decays in Au+Au collisions at sNN=200GeV. The nuclear modification factor RAA relative to p+p collisions shows a strong suppression in central Au+Au ...
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 438 pb-1 at centre-of-mass energies of /sqrt(s)=192-209 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level lower limit on the scalar top quark mass is /97.6 GeV ...
In next-to-leading order quantum chromodynamics, gluon-gluon interactions dominate the production of bottom quarks at hadron collider energies, and gluon-quark interactions control inclusive prompt photon production at large transverse momentum in pp coll...
We investigate the quark masses and mixings by including vector-like down-type quark singlets in universality of strength for Yukawa couplings (USY). In contrast with the standard model with USY, the sufficient CP violation is obtained for the Cabibbo Kobayashi Maskawa matrix through the mixing between the ordinary quarks and ...
Elastic scattering of charm (c) and bottom (b) quarks via D- and B-meson resonance states in an expanding, strongly interacting quark-gluon plasma is investigated. Drag and diffusion coefficients are calculated from an effective model based on chiral symmetry and heavy-quark effective theory, and utilized in a ...
The presentations at the Fifth Moriond Workshop on Heavy Quarks, Flavor Mixing, and CP Violation (La Plagne, France, January 13-19, 1985) are summarized. The following topics are reviewed. What's New (beyond the top, top quarks, bottom quarks, charm quarks, strange ...
Recently, it has been demonstrated that the chemical composition of jets in heavy ion collisions is significantly altered compared to the jets in the vacuum. This signal can be used to probe the medium formed in nuclear collisions. In this study we investigate the possibility that fast light quarks and gluons can convert to heavy quarks when passing ...
We report results of three searches for scalar top quark. Two of the searches look for direct production of scalar top quark followed by the decay of the scalar quark to charm quark and neutralino or bottom and chargino. The third search looks for top quark decaying to ...
Production, elliptic flow and the nuclear modification factor of charm and bottom quarks are studied in central and non-central heavy-ion collisions at RHIC and LHC using the partonic transport model Boltzmann Approach of MultiParton Scatterings (BAMPS). Employing an initial heavy quark yield obtained with PYTHIA the full space-time ...
We analyze the implications of the infrared quasi fixed point solution for the top quark mass in the Minimal Supersymmetric Standard Model. This solution could explain in a natural way the relatively large value of the top quark mass and, if confirmed experimentally, may be suggestive of the onset of nonperturbative physics at very high energy scales. In ...
We investigate the uncertainties of the heavy-quark parton distribution functions in the variable avor number scheme. Because the charm- and bottom-quark parton distribution functions (PDFs) are constructed predominantly from the gluon PDF, it is a common practice to assume that the heavy-quark and gluon uncertainties are the same. We ...
The drag and diffusion coefficients of charm and bottom quarks propagating through quark gluon plasma (QGP) have been evaluated for conditions relevant to nuclear collisions at the Large Hadron Collider (LHC). The dead cone and Landau-Pomeronchuk-Migdal (LPM) effects on radiative energy loss of heavy quarks have ...
A quark action designed for highly anisotropic-lattice simulations is discussed. The mass-dependence of the parameters in the action is studied and the results are presented. Applications of this action in studies of heavy quark quantities are described and results are presented from simulations at an anisotropy of six, for a range of ...
Theoretical developments in the dynamics of heavy quark production in hadronic collisions as well as recent data are discussed. Focus is principally on bottom quark production. Extensive calculations of cross sections and production spectra for both collider and fixed target energies are presented. Available data are in excellent ...
The theory of heavy quark production in QCD at collider energies is reviewed. The most important features of the recently published results on higher order corrections to the heavy quark production cross-section are described. The phenomenological consequences of these formulae for bottom and top quark production ...
the isotropic and anisotropic lattices we work with one light quark mass slightly heavier than the strange quark. On the anisotropic lattice we accummulated results for two heavy quark masses, one around the bottom quark'' masses are very close to each other on the isotropic and anisotropic ...
A recently proposed powerlike phenomenological potential which gives an excellent fit of the meson spectrum from strange quark bound states to bottom quark states is extrapolated to the baryons. The omega exp - , omega sub(c) and omega sub(b) masses are c...
Recent experiments have obtained large clean samples of charmed and bottom hadrons, and have measured both single-quark inclusive cross-sections and quark-antiquark correlations. Predictions for these production properties are available from next-to-leadi...
The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be ...
In grand unified theories (GUT) based on SO(10) all fermions of one generation are embedded in a single representation. As a result, the top quark, the bottom quark, and the (tau) lepton have the same Yukawa coupling at the GUT scale. This implies a very ...
Significant progress has been made in the determination of the light quark masses, using both lattice QCD and sum rule methods, in the last year. The authors discuss the different methods and review the status of current results. Finally, they review the calculation of bottom and charm masses.
A review is presented of heavy quark in /bar p/p, p, and pp interactions at fixed target and collider energies. Calculations of total cross sections are described, including contributions through next-to-leading order in QCD perturbation theory. Comparisons with available data on charm and bottom quark production show good agreement ...
A review is presented of heavy quark production in /bar p/p, p, and pp interactions at fixed target and collider energies. Calculations of total cross sections are described including contributions through next-to-leading order in QCD perturbation theory. Comparisons with available data on charm and bottom quark production show good ...
We discuss the calculation of open heavy flavor cross sections at RHIC and describe how the semileptonic decays of charm and bottom quarks can be separated.
... A study of the production of particles containing charm or bottom quarks in 300-GeV neutron interactions using a high-resolution streamer chamber ...
DTIC Science & Technology
Author(s): Thieman, J.; Roberts, A.; King, T.; King, J.; Harvey, C. ... For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the . ...
For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the classical model agrees with the ... NASA Center: Goddard Space Flight Center ...
We present a top search analysis of W+jet events which combines a study of the kinematic features of the events with a search for bottom quarks.
at muons and antimuons emerging from the decays of neutral mesons containing bottom quarks, which is a source that we have long expected is a fruitful place to study the...
For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the ... NASA Center: Goddard Space Flight Center Publication Year: 2009 ...
Searches for a scalar top quark and a scalar bottom quark have been performed using a data sample of 182 pb-1 at a centre-of-mass energy of sqrt(s)=189 GeV collected with the OPAL detector at LEP. No evidence for a signal was found. The 95% confidence level (C.L.) lower limit on the scalar top quark mass is 90.3 ...
Charm quarks are produced during the early stages of collision, making it a powerful probe of the hot and dense medium created at RHIC. Its measurement through the semi-leptonic decay channel can provide some insight, although the relative yield of charm and bottom are highly uncertain in such measurements. It is essential to disentangle charm and ...
We have searched for direct production of scalar top quarks at the Collider Detector at Fermilab in 88 pb(-1) of p&pmacr; collisions at sqrt[s] = 1.8 TeV. We assume the scalar top quark decays into either a bottom quark and a chargino or a bottom quark, a lepton, and a ...
A review is presented of heavy quark production in {bar p}p, {pi}{sup -}p, and pp interactions at fixed target and collider energies. Calculations of total cross sections and of single quark inclusive differential cross sections d{sup 2}{omega}/dk{sub T}dy are described including contributions through next-to-leading order in QCD perturbation theory. ...
After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.
The status of Fixed Target experiments to study charm and bottom is reviewed. The physics motivation for further high statistics studies of charm and bottom is presented. The technical challenges which will be encountered in doing very high sensitivity st...
We discuss the results of a full calculation of the QCD O( alpha sub 8 /sup s/) radiative corrections to the differential cross section for the production of a heavy quark pair. Numerical results are presented for bottom and top production in p/bar p/ col...
This paper addresses the issue of production of charm orbottom quarks in association with a high pT process in hadron hadroncollision. These quarks can be produced either as part of the hardscattering process or as a remnant from the structure functions. Thelatter sums terms of the type (alpha_s log(pT/mq))n. If structurefunctions of charm or ...
The masses of S-wave bottom baryons are calculated in the framework of coupled-channel formalism. The relativistic three-quark equations for the bottom baryons using the dispersion relation technique are found. The approximate solutions of these equations based on the extraction of leading singularities of the amplitude are obtained. ...
Charm- and bottom-quark rescattering in a quark-gluon plasma (QGP) is investigated with the objective of assessing the approach toward thermalization. Employing a Fokker-Planck equation to approximate the collision integral of the Boltzmann equation we augment earlier studies based on perturbative parton cross sections by introducing resonant heavy-light ...
The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < p{sub rmT} < 9 GeV/c at midrapidity (|y| < 0.35) from heavy flavor (charm and bottom) decays in Au+Au collisions at {radical}s{sub NN} = 200 GeV. The nuclear modification factor R{sub AA} relative to p+p collisions shows a strong ...
The discovery of the top quark in 1995, by the D0 and CDF collaborations, was the culmination of nearly two decades of intense research at accelerators around the world. Since then, both collaborations have done precise measurements of the top quark properties, in particular its mass and production cross section. The top quark's large ...
This document reviews recent results on the search for scalar top and scalar bottom quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The analyses presented are based on data samples with integrated luminosities from 1.0 to 1.9 fb{sup -1} recorded at the Tevatron with the D0 and CDF detectors.
This document reviews recent results on the search for scalar top and scalar bottom quarks in pp collisions at s = 1.96 TeV. The analyses presented are based on data samples with integrated luminosities from 1.0 to 1.9 fb-1 recorded at the Tevatron with the D0 and CDF detectors.
Recent results from various Fermilab experiments on the hadroproduction of states containing charm, bottom, and top quarks are discussed. These include observation of the spectra, lifetime, and production characteristics of charmonium, open charm states, and bottom particle production with both high energy fixed target and {bar p}-p ...
Recent results from various Fermilab experiments on the hadroproduction of states containing charm, bottom, and top quarks are discussed. These include observation of the spectra, lifetime, and production characteristics of charmonium, open charm states, and bottom particle production with both high energy fixed target and (p bar)-p ...
The region of small transverse momentum in q{bar q} and gg-initiated processes must be studied in the framework of resummation to account for the large, logarithmically-enhanced contributions to physical observables. In this letter, we study resummed differential cross-sections for Higgs production via bottom-quark fusion. We find that the differential distribution peaks at ...
We present predictions for the rapidity and transverse momentum distributions for inclusive production of bottom quarks at SSC energies, pp ..-->.. bX. Our computations are based on the simplest, lowest-order QCD mechanisms. To estimate uncertainties, we use three different choices for structure functions, G(x,Q), as well as different choices for the ...
Calculations of inclusive cross sections for the production of bottom quarks in proton-proton collisions are presented as a function of energy, transverse momentum, and Feynman x{sub F} for values of {radical}s from 100 GeV to 40 TeV. In addition, we provide simple parametrizations of our theoretical results that should facilitate estimates of rates, ...
Searches for the supersymmetric partners of top and bottom quarks using data up to 340 pb{sup -1} taken at the Tevatron p{bar p} collider are described. We report on searches for scalar top quarks {tilde t} in the decays {tilde t} {yields} c{tilde {chi}}{sub 1}{sup 0} and {tilde t} {yields} bl{tilde v} and for scalar ...
In next-to-leading order quantum chromodynamics, gluon-gluon interactions dominate the production of bottom quarks at hadron collider energies, and gluon-quark interactions control inclusive prompt photon production at large transverse momentum in [ital pp] collisions at fixed-target energies. Using such data, in conjunction with data ...
In next-to-leading order quantum chromodynamics, gluon-gluon interactions dominate the production of bottom quarks at hadron collider energies, and gluon-quark interactions control inclusive prompt photon production at large transverse momentum in pp collisions at fixed-target energies. Using such data, in conjunction with data from ...
With the first evidence for single top quark production in the D0 detector at the Fermilab Tevatron pp collider, the single top quark cross section is measured, limits on the masses of heavy W' boson resonances are set and anomalous Wtb couplings are studied.
With the first evidence for single top quark production in the D0 detector at the Fermilab Tevatron pp-bar collider, the single top quark cross section is measured, limits on the masses of heavy W' boson resonances are set and anomalous Wtb couplings are studied.
We develop a holographic (bottom-up) gravity model for QCD to understand the connection between the peak in the trace anomaly and the magnitude of heavy quark energy loss in a strongly-coupled plasma. The potential of the scalar field on the gravity side is constructed to reproduce some properties of QCD at finite temperature and its parameters are ...
We present complete one-loop radiative corrections to the decay rate of a top quark into a charged Higgs boson and a bottom quark, and for the decay of a charged Higgs boson into leptons. The results are discussed in the framework of the two-Higgs-boson extension of the standard model suggested by supersymmetry. The effect of ...
Models of electroweak symmetry breaking with more than a single doublet of Higgs scalars contain a neutral pseudoscalar boson. The production of such a pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a top-quark loop (except for those models in which the pseudoscalar coupling to bottom quarks is strongly ...
We construct a supersymmetric model where the left-handed top and bottom quarks are mainly the gauginos of a vector supermultiplet and hence their superpartners are spin 1. The right-handed top quark is unified with the Higgs field; the top Yukawa coupling arises from the gaugino coupling. PMID:18999742
Decay processes of ground and excited bottom baryons are studied in the 3P0 nonrelativistic quark model with all model parameters fixed in the sector of light quarks. Using as an input the recent mass of ?b and the theoretical masses of ?b* and ?b', narrow decay widths are predicted for the ground-state bottom ...
We report the results on the transverse momentum spectra of {phi} mesons and {omega} ({omega}- + {omega}(bar sign)+) baryons as well as their anisotropic flows in Au+Au collisions at RHIC, obtained from a dynamical quark coalescence model that uses the quark phase-space information from a multi-phase transport (AMPT) model within the ...
The nuclear modification factor R{sub AA} of nonphotonic electrons in Au+Au collisions at {radical}(s{sub NN})=200 GeV is studied by considering the decays of heavy-flavor hadrons produced in a quark coalescence model. Although an enhanced {lambda}{sub c}/D{sup 0} ratio is predicted by the coalescence model, it is peaked at small transverse momenta ...
A theory is presented based on QCD and Dirac equation solutions with well-defined energy, momentum, and angular momentum for quarks and gluons. Dynamic chiral symmetry breaking occurs when massless quarks and gluons have identical velocities resulting in color electric fields being cancelled by countervailing color magnetic fields. Massless ...
In the MSSM with complex parameters, loop corrections to the decay of a stop into a bottom quark and a chargino can lead to a CP violating decay rate asymmetry. We calculate this asymmetry at full one-loop level and perform a detailed numerical study, analyzing the dependence on the parameters and complex phases involved. In addition, we take the Yukawa ...
There are several motivations for studying masses and lifetimes of the hadrons containing a heavy quark, either the bottom or the charm quark. First, the mass and the lifetime are fundamental properties of an elementary particle. Second, the spectroscopy of hadrons gives insights into the QCD potential between ...
The study of b quarks at high energy hadron colliders tests the Standard Model in regions of small {chi} and high transverse momentum. The method used to measure the b quark cross section using the semileptonic decay to muons is outlined. A preliminary CDF muon cross section is given using data from the 88--89 run, and a plot of the measured b ...
The study of b quarks at high energy hadron colliders tests the Standard Model in regions of small [chi] and high transverse momentum. The method used to measure the b quark cross section using the semileptonic decay to muons is outlined. A preliminary CDF muon cross section is given using data from the 88--89 run, and a plot of the measured b ...
The new heavy-light meson states are discussed within a constituent quark model that provides with a good description of the rest of the meson and baryon spectra and also the baryon-baryon phenomenology. All these resonances are properly describes if considered as a mixture of conventional quark-antiquark states and four-quark ...
We extend our work on QCD thermodynamics with 2+1 quark flavors at nonzero chemical potential to finer lattices with N{sub t}=6. We study the equation of state and other thermodynamic quantities, such as quark number densities and susceptibilities, and compare them with our previous results at N{sub t}=4. We also calculate the effects of the addition of ...
The heavy-quark expansion for inclusive semi-leptonic B decays introduces {Lambda} and {lambda}1 , which are matrix elements in heavy-quark effective field theory. We review how they can be obtained from an analysis of the heavy quark mass dependence of heavy-light meson masses in lattice QCD. We present preliminary results for the ...
We present an exact calculation of S and P wave QQnn states using different standard nonrelativistic quark-quark potentials. We explore in detail the charm and bottom sectors looking for bound states that could be measured within existing facilities. Against the proliferation of four-quark states sometimes predicted in the literature, ...
A good agreement between a flux tube-based quark model of light baryons (strange and nonstrange) and the 1/Nc expansion mass formula has been found in previous studies. In the present work a larger connection is established between the quark model and the 1/Nc and 1/mQ expansion method by extending the previous procedure to baryons made of one heavy and ...
Measurements of electrons from the decay of open-heavy-avor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled p+p collisions. These measurements indicate that charm and bottom quarks interact with the hot-dense matter produced in heavy-ion collisions much more than ...
Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled p+p collisions. These measurements indicate that charm and bottom quarks interact with the hot dense matter produced in heavy-ion collisions much more than ...
Masses of tetraquarks with two heavy quarks and open charm and bottom are calculated in the framework of the diquark-antidiquark picture in the relativistic quark model. All model parameters were regarded as fixed by previous considerations of various properties of mesons and baryons. The light quarks and diquarks ...
The heavy fourth generation of quarks that have sufficiently small mixing with the three known standard model families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from the fourth family and the other from known third family standard model ...
A sample of three-jet events containing a lepton with high momentum and transverse momentum is selected from hadronic decays of the Z0. The presence of the lepton indicates the semi-leptonic decay of a bottom quark and allows us, in combination with energy ordering of the jets, to distinguish between quark and gluon jets. The sign of ...
The top quark was discovered in 1995 at the Fermilab National Accelerator Laboratory (Fermilab). One way to confirm if the observed top quark is really the top quark posited in the Standard Model (SM) is to measure its electric charge. In the Standard Model the top quark is the isospin partner of the ...
Bottom baryon masses are calculated based on a 2+1 flavor dynamical lattice QCD simulation. The gauge field configurations were computed by the CP-PACS and JLQCD collaborations using an improved clover action. The bottom quark is described using lattice NRQCD. Results are presented for single and double-b baryons at one lattice ...
The PHENIX experiment has measured electrons from the decay of hadrons carrying heavy flavor (charm or bottom quarks) in p + p and Au + Au collisions at {radical}s{sub NN} = 200 GeV at the Relativistic Heavy Ion Collider (RHIC). The strong damping of heavy-flavor motion through the medium is reflected in a ...
Non-photonic electrons (p>3�GeV/c) represent the directions of the parent heavy quarks, and their angular correlations with charged hadrons provide a good tool to study the relative contributions from D and B meson decays in p+p collisions, as well as the flavor-dependence of the energy loss mechanism in A+A collisions. We review the disentanglement of charm and ...
First observed in 1995, the top quark is one of a pair of third-generation quarks in the Standard Model of particle physics. It has charge +2/3e and a mass of 171.4 GeV, about 40 times heavier than its partner, the bottom quark. The CDF and DO collaborations have identified several hundred events containing the ...
The production and space-time evolution of charm and bottom quarks in nucleus-nucleus collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC) are investigated with the partonic transport model BAMPS (Boltzmann approach of multiparton scatterings). Heavy quarks, produced in primary hard ...
The discussion covers quarks as we know them, the classification of ordinary mesons in terms of constituent quarks, hidden charm states and charmed mesons, bottom quarks, positronium as a model for quarti q, quantum chromodynamics and its foundation in experiment, the charmonium model, the mass of states, fine ...
We consider a class of seven-dimensional N=1 supersymmetric orbifold GUTs in which the standard model (SM) gauge couplings and one of the Yukawa couplings (top quark, bottom quark or tau lepton) are unified, without low-energy supersymmetry, at M{sub GUT}{approx_equal}4x10{sup 16} GeV. With gauge-top quark Yukawa ...
Models based on Universal Extra Dimensions predict Kaluza-Klein (KK) excitations of all Standard Model (SM) particles. We examine the pair production of KK excitations of top- and bottom-quarks at the Large Hadron Collider. Once produced, the KK top/bottom quarks can decay to b-quarks, leptons and the lightest ...
A review is presented of heavy quark production in {bar p}p, {pi}{sup -}p, and pp interactions at fixed target and collider energies. Calculations of total cross sections and of single quark inclusive differential cross sections d{sup 2}{sigma}/dk{sub T}dy are described including contributions through next-to-leading order in QCD perturbation theory. ...
We compute the exact two-loop matching coefficient for the bottom-quark mass m{sub b}, within the Minimal Supersymmetric Standard Model (MSSM), taking into account O({alpha}{sub s}{sup 2}) contributions from the Supersymmetric Quantum Chromodynamics (SQCD). We find that the three-loop order corrections to the running bottom-quark mass exceed the ...
This thesis reports a measurement of the average lifetime of hadrons containing bottom quark. It is based on data taken with the DELCO detector at the PEP e/sup +/e/sup -/ storage ring at a center of mass energy of 29 GeV. The decays of hadrons containing bottom quarks are tagged in hadronic events by the presence ...
We investigate the prospects for the discovery at the CERN Large Hadron Collider (LHC) of a neutral Higgs boson produced with one bottom quark followed by Higgs decay into a muon pair. We work within the framework of the minimal supersymmetric model. The dominant physics background from the production of b mu(+)mu(-), j mu(+)mu(-), j=g,u,d,s,c, and bbW+W- ...
This dissertation describes the measurement of the top quark mass using events recorded during a {approx} 230 pb{sup -1} exposure of the D0 detector to proton-anti-proton (p{bar p}) collisions at a center of mass energy of 1.96 TeV. The Standard Model of particle physics predicts that the top quark will decay into a bottom ...
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3<p{sub T}<9 GeV/c at midrapidity (vertical bar y vertical bar <0.35) from heavy-flavor (charm and bottom) decays in Au+Au collisions at {radical}(s{sub NN})=200 GeV. The nuclear modification factor R{sub AA} relative to p+p collisions ...
The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3<p{sub T}<9 GeV/c at midrapidity (|y|<0.35) from heavy-flavor (charm and bottom) decays in Au+Au collisions at {radical}(s{sub NN})=200 GeV. The nuclear modification factor R{sub AA} relative to p+p collisions shows a strong ...
As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon that originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot ...
We report the results of a search for pair production of scalar bottom quarks (b) and scalar third-generation leptoquarks (LQ) in 5.2 fb?1 of pp� collisions at the D0 experiment of the Fermilab Tevatron Collider. Scalar bottom quarks are assumed to decay to a neutralino (?�10) and a b ...
An SO(5)xU(1) gauge-Higgs unification model in the Randall-Sundrum warped space with top and bottom quarks is constructed. Additional fermions on the Planck brane make exotic particles heavy by effectively changing boundary conditions of bulk fermions from those determined by orbifold conditions. Gauge couplings of a top quark ...
This thesis studies Monte Carlo simulations of QCD heavy flavor production processes (p{bar p} {yields} Q({anti Q})X) at hadron colliders. ISAJET bottom quark cross-sections are compared to the O({alpha} {sub s}{sup 3}) perturbative calculation of Nason, Dawson, and Ellis. These Monte Carlo cross-sections are computed from data samples which use different ...
Differential distributions for heavy quark production depend on the heavy quark mass and other momentum scales, which can yield additional large logarithms and inhibit accurate predictions. Logarithms involving the heavy quark mass can be summed in heavy quark parton distribution functions in the ...
Nonperturbative charm and bottom quark-pair production is investigated in the early stage of heavy-ion collisions. The time-dependent study is based on a kinetic description of fermion-pair production in strong non-Abelian fields. We introduce a time-dependent chromo-electric external field with a pulselike time evolution to simulate the overlap of two ...
Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isos...
We present a supersymmetric renormalization group fixed point determination of the third generation fermion masses, in which the large mass ratio between the top and bottom quarks is attributed to a hierarchy in the vacuum expectation values of the two Hi...
Recent results from various Fermilab experiments on the hadroproduction of states containing charm, bottom, and top quarks are discussed. These include observation of the spectra, lifetime, and production characteristics of charmonium, open charm states, ...
Within QCD the photoproduction of new heavy flavours proceeds via photon-gluon amalgamation. The production cross sections of new particles (charm, top, bottom, ...) are calculated. Photon and lepton beams are better suited than hadron beams for producing the new particles.
This thesis is devoted to the study of some supersymmetric quarks such as s- top and s-bottom. This investigation field is all the more interesting since the weak mass of these squarks could be explained by the strong Yukawa coupling between top and botto...
The author summarizes the studies on the hadronic production of S- and P-wave ({bar b}c) mesons via direct fragmentation of the bottom antiquark as well as the Altarelli-Parisi induced gluon fragmentation.
Predictions are presented of total cross sections for charm and bottom quark production in /bar p/p, pi /sup /minus//p, and pp interactions at fixed target and collider energies. The calculations are done through next-to-leading order in QCD perturbation ...
We use the field correlator method in QCD to calculate the masses of {Sigma}{sub c}, {Xi}{sub c}, and recently observed {Sigma}{sub b}, {Xi}{sub b} baryons and their orbital excitations.
The large heavy quark production cross section in p{bar p} collisions makes the Tevatron an excellent place to study charm and bottom physics. This allows for a rich program of spectroscopy, CP parameter measurements, and searches for new physics.
We perform a joint analysis of the prediction of composite Higgs models for the discrepancies of the forward-backward asymmetries of top and bottom quarks at Tevatron and LEP + SLC, respectively. We build a two sector model which can be thought as an effective low energy description of 5D warped models and choose the quantum numbers of the fermionic ...
We explore possible ways of explaining the net charge event-by-event fluctuations in Au+Au collisions observed in experiments at the Relativistic Heavy Ion Collider within a quark recombination model. We estimate the number of quarks at recombination and their implications for the predicted net charge fluctuations. We also discuss the ...
of the experimental data in Au+Au collisions at RHIC showed features speci#12;c of valence quark coalescence: enhancement to the single elctron data, we employ a Fokker-Planck approach for c and b quarks in the QGP based on elastic with the number of valence quarks, are robust e#11;ects against improvements of the ...
We calculate the large top quark mass expansions for the H ! bb decay rate in the order ff 2 s and for the H ! gluons decay rate in the order ff 3 s . The obtained expansions rapidly converge in the region of their validity, MH ! 2m t , i.e. below the threshold of tt production. 1 Introduction With the discovery of the top quark [1], the Higgs boson ...
Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it tends to decay before forming a bound ...
Inclusive bottom hadron decays are analyzed based on the heavy quark effective field theory (HQEFT). Special attentions in this paper are paid to the b?u transitions and nonspectator effects. As a consequence, the CKM quark mixing matrix elements |Vub| and |Vcb| are reliably extracted from the inclusive semileptonic decays B?Xue? and ...
We analyze the quantum transport equations for supersymmetric electroweak baryogenesis including previously neglected bottom and tau Yukawa interactions and show that they imply the presence of a previously unrecognized dependence of the cosmic baryon asymmetry on the spectrum of third generation quark and lepton superpartners. For fixed values of the ...
Measurement of the tau lifetime checks whether the tau couples to the charged weak current with the same universal coupling strength as the e and ..mu... The lifetime of bottom hadrons measures the weak coupling between the bottom quark and the charm and up quarks. Measurements of these lifetimes have been made ...
We discuss the feasibility of seeing a Higgs boson which decays to four bottom quarks through a pair of (pseudo-)scalars at the LHCb experiment to argue that the use of b-physics triggers and off-line vertex reconstruction, as opposed to jet triggers with b tagging, may be more effective for this signal. Focusing on inclusive production for the Higgs, we ...
Searches for the lightest scalar top quark {bar t}{sub 1} and scalar bottom quark {bar b}{sub 1} performed at LEP2 with a center-of-mass energy of up to {radical}s = 209 GeV and at Tevatron using data collected at {radical}s = 1.8 TeV during Run I and at {radical}s = 1.96 TeV during Run II, are discussed. Different possible decay modes ...
The lifetime differences of bottom hadrons are known to be properly explained within the framework of heavy quark effective field theory (HQEFT) of QCD via the inverse expansion of the dressed heavy quark mass. In general, the spectrum around the endpoint region is not well behaved due to the invalidity of 1/mQ expansion near the ...
The author reviews the color dipole formulation of heavy quark production in the light of recent RHIC data. Since charm and bottom production directly probe the gluon density, these processes allow one to study shadowing and parton saturation at RHIC and LHC. The dipole approach provides a convenient framework to calculate these nuclear effects. I present ...
We study inclusive heavy quark and exclusive heavy quark pair production in pp, pA and AA interactions. Intrinsic transverse momentum is introduced in pp interactions. Nuclear effects, limited to k{sub T} broadening and nuclear shadowing, are introduced in pA and AA interactions. The nuclear dependence is studied over a range of energies, both in fixed ...
The supersymmetric decays of the top quark into charged Higgs plus bottom, t (yields) H(sup +)b, and into the supersymmetric partner of the top (u(sub 1)) plus the lightest neutralino ((chi)(sub 1)(sup 0)), t (yields) u(sub 1)(chi)(sub 1)(sup 0), are disc...
We examine the possibility of finding charged Higgs bosons (H sup +- ) at the SSC. The charged Higgs boson is produced with a top quark via a gluon + bottom quark interaction (g + b -> H + t). For the two Higgs doublet models, H sup +- decays predominantl...
We present an improved search for quark fusion production qq'->H^+ of the charged Higgs boson reconstructed in the tb final state using 5.4 fb-1 of data collected by the D0 detector. We find no evidence for charged Higgs production and set limits on the production cross-section for a variety of theoretical models.
We study the current-induced bottom baryon to charm baryon transitions in the Heavy Quark Symmetry limit as m(sub q) (yields) (infinity). Our discussion involves s-wave to s-wave as well as s-wave to p-wave transitions. Using a constituent quark model pic...
The status of the determination of the quark mixing matrix in the Kobayashi-Maskawa model and its phenomenological implications are discussed. Much of the talk reviews current work on the subject. Some new results on the CP violation effects in exclusive and inclusive decays of bottom, charm and strange particles are also given.
INTERVIEW Tevatron prepares to be very intense Roger Dixon is head of the accelerator division at Fermilab in Batavia, Illinois. Fermilab's Tevatron, a proton-antiproton collider second only in size and speed to the Large Hadron Collider, has been used to discover two major components of the Standard Model: the bottom quark (May-June 1977) and the top ...
From a sample of hadronic events produced in e+e- collisions, semileptonic decays of heavy particles have been isolated and used to obtain a measurement for the bottom-quark lifetime of [1.8+/-0.6 (stat.)+/-0.4(syst.)]�10-12 sec.
We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{anti B} mixing results. An outlook of perspectives for top ...
At the LHC associated top quark and Higgs boson production with a Higgs boson decay to bottom quarks has long been a heavily disputed search channel. Recently, it has been found not to be viable. We show how it can be observed by tagging massive Higgs bosons and top jets. For this purpose we construct boosted top and Higgs taggers for ...
The work exposed in this thesis deals with the search for electroweak production of top quark (single top) in proton-antiproton collisions at {radical}s = 1.96 TeV. This production mode has not been observed yet. Analyzed data have been collected during the Run II of the D0 experiment at the Fermilab Tevatron collider. These data correspond to an integrated luminosity of 370 ...
at an anisotropy of six, for a range of quark masses from strange to bottom. I. INTRODUCTION The anisotropic potentially spoils the bene#12;ts of working on an anisotropic lattice, especially at large quark masses. In Ref no exceptional con#12;gurations were seen. B. E#11;ective masses The success of anisotropic lattice methods is ...
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objectives of this project were (1) to develop the computer code necessary for the simulation of heavy quarks using the nonrelativistic quantum chromodynamics (NRQCD) approach using the massively parallel Connection Machine CM-5; and ...
The bound state of a quark and an anti quark, quarkonium, is discussed as a means to investigate the nature of the strong force. An analogy is made between positronium and quarkonium and quantum electrodynamics which describes positronium and quantum chromodynamics which describes quarkonium. There is a review of basic concepts applicable to both systems ...
Heavy gauge bosons such as W' are expected to exist in many extensions of the Standard Model. In this paper, the most general Lagrangian for the interaction of W' with top and bottom quarks is considered. This Lagrangian consists of V-A and V+A structure with in general complex couplings. Such interactions produce an Electric Dipole Moment (EDM) for the ...
The J/{psi} is considered to be among the most important probes for the deconfined quark gluon plasma (QGP) created by relativistic heavy ion collisions. While the J/{psi} is thought to dissociate in the QGP by Debye color screening, there are competing effects from cold nuclear matter (CNM), feed-downs from excited charmonia ({chi}{sub c} and {psi}{prime}) and ...
Decay rates of unpolarized top quarks into longitudinally and transversally polarized W bosons are calculated to second order in the strong coupling constant {alpha}{sub s}. Including the finite bottom quark mass and electroweak effects, the standard model predictions for the W-boson helicity fractions are F{sub L}=0.687(5), F{sub ...
We present the CTEQ6HQ parton distribution set which is determined in the general variable flavor number scheme which incorporates heavy flavor mass effects; hence, this set provides advantages for precision observables which are sensitive to charm and bottom quark masses. We describe the analysis procedure, examine the predominant features of the new ...
We calculate one-loop R-parity violating corrections to the top quark decay into a bottom quark and a polarized W-gauge boson. The corrections are presented according to the total corrections, the longitudinal corrections and the transverse corrections, respectively. We compared our results with the O({alpha}{sub s}) QCD corrections, ...
We present the first results of next-to-leading order QCD corrections to three-jet heavy quark production at the CERN e{sup +}e{sup {minus}} collider LEP including mass effects. Among other applications, this calculation can be used to extract the bottom-quark mass from LEP data and, therefore, to test the running of masses as predicted by QCD. {copyright} ...
Important goals of BNL RHIC and CERN LHC experiments with ion beams include the creation and study of new forms of matter, such as the quark gluon plasma. Heavy quark production and attenuation provide unique tomographic probes of that matter. We predict the suppression pattern of open charm and beauty in Au+Au collisions at RHIC and ...
Signatures of collective effects are studied in the Quark Gluon String Model and in the Fluid Dynamical Model for Au (plus) Au collisions at 11.6 A GeV. In the fluid dynamical model the dependence of measurables on the QGP formation in the EOS is pointed ...
In most of the mass range encompassed by the limits from the direct search and the electroweak precision tests, the Higgs boson of the standard model preferably decays to bottom quarks. We present, in analytic form, the dominant two-loop electroweak correction, of O(GF2mt4), to the partial width of this decay. It amplifies the familiar enhancement due to ...
We present a complete next-to-leading-order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion (bb{yields}hh) at the CERN Large Hadron Collider (LHC) in the standard model. The NLO QCD corrections lead to less dependence on the renormalization scale ({mu}{sub R}) and the factorization scale ({mu}{sub F}) than the ...
We present a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion (b{bar b} {yields} hh) at the CERN Large Hadron Collider (LHC) in the Standard Model. The NLO QCD corrections lead to less dependence on the renormalization scale ({mu}{sub R}) and the factorization scale ({mu}{sub F}) than the ...
