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After discussing the intrinsic ambiguity in determining the light quark mass ratio $m_u/m_d$, we reexamine the recent proposal that this ambiguity can be resolved by applying the QCD multipole expansion for the heavy quarkonium decays. It…

High Energy Physics - Phenomenology · Physics 2008-11-26 Kiwoon Choi

A generalization of the parton-like formula is used for the first time to find the differential distributions in the inclusive semileptonic weak decays of the B meson. The main features of this new approach are the treatment of the b-quark…

High Energy Physics - Phenomenology · Physics 2009-11-07 I. L. Grach , P. Yu. Kulikov , I. M. Narodetskii

I propose a controlled approximation to QCD-like theories with massless quarks by employing supersymmetric QCD perturbed by anomaly-mediated supersymmetry breaking. They have identical massless particle contents. Thanks to the…

High Energy Physics - Theory · Physics 2021-06-30 Hitoshi Murayama

We present the energy density and flux distribution of a heavy quark moving through high temperature QCD plasmas and compare them with those in the strongly coupled N = 4 SYM plasma. The Boltzmann equation is reformulated as a Fokker-Planck…

Nuclear Theory · Physics 2011-10-05 Juhee Hong

We consider mesons composed of light and heavy quarks and discuss the construction of the corresponding meson wave functions in soft-wall AdS/QCD. We specifically take care that constraints imposed by chiral symmetry breaking and by the…

High Energy Physics - Phenomenology · Physics 2013-03-04 Thomas Gutsche , Valery E. Lyubovitskij , Ivan Schmidt , Alfredo Vega

recently proposed strictly phenomenological static quark-antiquark potential belonging to the generality $V(r)=-Ar^{-\alpha}+\kappa r^{\beta}+V_{0}$ is tested with heavy quarkonia in the context of the shifted large N-expansion method. This…

High Energy Physics - Phenomenology · Physics 2009-11-11 Sameer M. Ikhdair , Ramazan Sever

The transition from the low $Q^2$ region in deep inelastic scattering where charm production is described by photon-gluon fusion to a region where the charm structure function $F_2^c$ is largely generated by a charm quark density should be…

High Energy Physics - Phenomenology · Physics 2009-10-30 R. S. Thorne , R. G. Roberts

We argue that consistency of the combined heavy quark and chiral effective lagrangian requires the QCD scale which multiplies $1/M$ in the heavy quark expansion to be the chiral symmetry breaking scale, $\Lambda_{CSB}$, rather than the QCD…

High Energy Physics - Phenomenology · Physics 2009-09-15 Lisa Randall , Eric Sather

An analytic result for the O(alpha_s corrections to the triple differential B -> X_u l nu decay rate is presented, to leading order in the heavy-quark expansion. This is relevant for computing partially integrated decay distributions with…

High Energy Physics - Phenomenology · Physics 2015-06-25 F. De Fazio , M. Neubert

We show that for a heavy vector-like quark model with a down type isosinglet, branching ratio for $c\rightarrow u\gamma$ decay is enhanced by more than $\mathcal{O}(10^2)$ as compared to that in the Standard model when QCD corrections to…

High Energy Physics - Phenomenology · Physics 2018-12-26 Aritra Biswas , Sanjoy Mandal , Nita Sinha

The moments of the heavy quark-parton distribution functions in a heavy pseudoscalar meson are calculated from QCD sum rules. Expanding these sum rules in the inverse heavy quark mass we obtain the heavy-mass limits of the moments.…

High Energy Physics - Phenomenology · Physics 2011-06-02 A. G. Oganesian

We review the NLL QCD calculations for the branching ratio of B -> X_s gamma in the SM. In particular, we emphasize the problem related to the definition of the charm quark mass which leads to a rather large uncertainty of the NLL…

High Energy Physics - Phenomenology · Physics 2014-11-17 Kay Bieri , Christoph Greub

The Bakamjian-Thomas relativistic quark model provides a Poincar\'e representation of bound states with a fixed number of constituents and, in the heavy quark limit, form factors of currents satisfy covariance and Isgur-Wise scaling. We…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Le Yaouanc , L. Oliver , J. -C. Raynal

The dynamics of {\it light} fermions propagating in a spatial direction at high temperatures can be described effectively by a two--dimensional Schr\"odinger equation with {\it heavy} effective mass $m_{\rm eff} = \pi T$. Starting from QED,…

High Energy Physics - Phenomenology · Physics 2014-11-17 V. Koch , E. V. Shuryak , G. E. Brown , A. D. Jackson

Dipole radiation in QCD is derived to the second order in $\alpha_s$. A power-like evolution of the spin-singlet heavy quark operators is obtained to the same accuracy. In particular, ${\cal O}(\alpha_s^2)$ relation between a short-distance…

High Energy Physics - Phenomenology · Physics 2009-10-30 Andrzej Czarnecki , Kirill Melnikov , Nikolaj Uraltsev

We study the radiative leptonic $B_c\to \gamma\ell\bar\nu$ decays in the nonrelativistic QCD effective field theory, and consider a fast-moving photon. As a result the interactions with the heavy quarks can be integrated out, and thus we…

High Energy Physics - Phenomenology · Physics 2015-10-14 Wei Wang , Rui-Lin Zhu

We investigate the in-medium modifications of heavy quarkonia in the vector channel and the heavy quark diffusion coefficient by comparing Euclidean correlators from the lattice to a perturbative spectral function. On the lattice side, we…

High Energy Physics - Lattice · Physics 2020-02-05 Anna-Lena Lorenz , Heng-Tong Ding , Olaf Kaczmarek , Hiroshi Ohno , Hauke Sandmeyer , Hai-Tao Shu

Phenomenological models of heavy flavour decays differ significantly in their predictions of global features of $B_c$ decays, like the $B_c$ lifetime or the relative weight of $c\ra s$ and $b\ra c$ transitions. The $1/m_Q$ expansion which…

High Energy Physics - Phenomenology · Physics 2009-10-28 I. I. Bigi

We analyze the double radiative B-meson decays B_s -> gamma gamma and B_d -> gamma gamma in QCD factorization based on the heavy-quark limit m_b >> Lambda_QCD. We systematically discuss the various contributions to these exclusive…

High Energy Physics - Phenomenology · Physics 2009-11-07 Stefan W. Bosch , Gerhard Buchalla

In a deep-infrared (ergodic) regime, QCD coupled to massive pseudoreal and real quarks are described by chiral orthogonal and symplectic ensembles of random matrices. Using this correspondence, general expressions for the QCD partition…

High Energy Physics - Theory · Physics 2009-10-31 T. Nagao , S. M. Nishigaki