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The redistribution in momentum space of heavy quarks via their interactions in the quark-gluon plasma is an excellent probe of the heavy quark coupling strength to the medium. We utilize a Monte Carlo Langevin calculation for tracking heavy…

Nuclear Theory · Physics 2014-09-05 Andrew M. Adare , Michael P. McCumber , James L. Nagle , Paul Romatschke

We study the complementarity between quark and lepton mixing angles (QLC), the sum of an angle in quark mixing and the corresponding angle in lepton mixing is $\pi/4$. Experimentally in the standard PDG parametrization, two such relations…

High Energy Physics - Phenomenology · Physics 2015-06-03 Guan-Nan Li , Hsiu-Hsien Lin , Xiao-Gang He

We propose the angular distribution of lepton pairs produced in ultrarelativistic heavy-ion collisions as a probe of thermalization of the quark-gluon plasma. We focus on dileptons with invariant masses large enough that they are produced…

Nuclear Theory · Physics 2024-06-07 Maurice Coquet , Xiaojian Du , Jean-Yves Ollitrault , Soeren Schlichting , Michael Winn

We present state-of-the art predictions for the production of supersymmetric squarks and gluinos at the Large Hadron Collider (LHC), including soft-gluon resummation up to next-to-next-to-leading logarithmic (NNLL) accuracy, the resummation…

High Energy Physics - Phenomenology · Physics 2017-02-01 Wim Beenakker , Christoph Borschensky , Michael Krämer , Anna Kulesza , Eric Laenen

This study examines the properties of heavy quarkonia $X$ by treating them as bound states of $Q$ and $\bar{Q}$ at the LO level within the NRQCD framework, where $Q$ represents either a charm or a bottom quark. The branching ratios for the…

High Energy Physics - Phenomenology · Physics 2024-07-19 Junle Pei , Xinchou Lou , Yaquan Fang , Jinfei Wu , Manqi Ruan

Two-loop contributions to the electromagnetic form factors are calculated in the kinematic regime close to the fermion-antifermion threshold. The results are presented in an expansion in the velocity $\beta$ of the fermions in the c.m.…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. H. Hoang

Recent measurements of J/psi production in e^+ e^- colliders pose a challenge to the NRQCD factorization theorem for quarkonium production. Discrepancies between leading order calculations of color-octet contributions and the momentum…

High Energy Physics - Phenomenology · Physics 2014-11-17 Thomas Mehen

The total cross section for the production of massive quarks in electron positron annihilation can be predicted in perturbative QCD. After expansion in m^2/s the quartic terms, i.e. those proportional to m^4/s^2, are calculated up to order…

High Energy Physics - Phenomenology · Physics 2009-10-31 K. G. Chetyrkin , R. V. Harlander , J. H. Kuehn

We analyze the proton electromagnetic form factor ratio $R(Q^{2})=QF_2(Q^{2})/F_1(Q^{2})$ as a function of momentum transfer $Q^{2}$ within perturbative QCD. We find that the prediction for $R(Q^{2})$ at large momentum transfer $Q$ depends…

High Energy Physics - Phenomenology · Physics 2008-11-26 Pankaj Jain , John P. Ralston

We present a QCD based interpretation of heavy quark fragmentation which utilizes the heavy quark mass expansion. By distinguishing between perturbative and non-perturbative QCD effects, we show how to reliably extract mass independent…

High Energy Physics - Phenomenology · Physics 2009-09-15 R. L. Jaffe , L. Randall

We present a calculation of the heavy quark momentum diffusion coefficients in a quark-gluon plasma under the presence of a strong external magnetic field, within the Lowest Landau Level (LLL) approximation. In particular, we apply the Hard…

High Energy Physics - Phenomenology · Physics 2022-07-26 Aritra Bandyopadhyay , Jinfeng Liao , Hongxi Xing

We present predictions for the nuclear modification factor and elliptic flow of D and B mesons, as well as of their decay electrons, in semicentral Pb-Pb collisions at the LHC. Heavy quarks are propagated in a Quark-Gluon Plasma using a…

High Energy Physics - Phenomenology · Physics 2008-04-22 H. van Hees , V. Greco , R. Rapp

We obtain new estimates for the parameters $\lambda_{E}^2$, $\lambda_H^2$ and their ratio $\mathcal{R} = \lambda_{E}^2/\lambda_H^2$, which appear in the second moments of the $B$-meson light-cone distribution amplitudes defined in the…

High Energy Physics - Phenomenology · Physics 2021-08-11 Muslem Rahimi , Marcel Wald

We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron…

High Energy Physics - Phenomenology · Physics 2017-03-08 S. J. Brodsky , V. A. Bednyakov , G. I. Lykasov , J. Smiesko , S. Tokar

We review in brief the threshold expansion, a method to perform the expansion of Feynman integrals near the heavy quark-antiquark threshold, and its relation to the construction of two effective theories, non-relativistic QCD (NRQCD) and…

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Beneke

We argue that a Tau-Charm factory (TCF) could improve our knowledge of CKM matrix elements since it is an incomparable tool to check the models and methods applied to extract $V_{bu}$ from $B$ decay partial widths. We report on some recent…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Le Yaouanc , O. Pène

Recent lattice QCD data on higher order susceptibilities of Charm quarks provide the opportunity to explore Charm quark equilibration in the early quark gluon plasma (QGP) phase. Here, we propose to use the lattice data on second and fourth…

High Energy Physics - Phenomenology · Physics 2018-03-14 Thorben Graf , Jan Steinheimer , Christoph Herold , Marcus Bleicher

When the energy of the heavy quark is comparable with its mass, it is natural to attribute this heavy quark to the hard part of the reaction. At large energies, this approach is impractical due to large logarithms from intensive QCD…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. M. Nadolsky , N. Kidonakis , F. Olness , C. -P. Yuan

Heavy quark transport coefficients in a strongly coupled Quark-Gluon Plasma can be evaluated using a gauge/string duality and lattice QCD. Via this duality, one can argue that for low momenta the drag coefficient for heavy quarks is…

High Energy Physics - Phenomenology · Physics 2018-04-04 Oleg Andreev

With the increasing experimental precision available at colliders, higher-order perturbative calculations are required to reduce the theory uncertainty in order to extract crucial QCD parameters, such as the strong coupling constant, to the…

High Energy Physics - Phenomenology · Physics 2022-08-15 Marco Saragnese