Nuclear Theory·nucl-th

Wednesday·December 28, 2016

10 papers—6 primary·4 cross-listed

07
Triple parton scatterings in proton-nucleus collisions at high energies
David d'Enterria🇨🇭 · Alexander M. Snigirev🇷🇺
A generic expression to compute triple parton scattering (TPS) cross sections in high-energy proton-nucleus (pA) collisions is derived as a function of the corresponding single-parton cross sections and an effective parameter encoding the transverse parton profile of the proton. The TPS cross sections are enhanced by a factor of $9 A \approx 2000$ in pPb compared to those in proton-nucleon collisions at the same center-of-mass energy. Estimates for triple charm ( $c c$ ) and bottom ( $b b$ ) production in pPb collisions at LHC and FCC energies are presented based on next-to-next-to-leading order (NNLO) calculations for $c c, b b$ single-parton cross sections. At $s_{N N} = 8.8$ TeV, about 10% of the pPb events have three $c c$ pairs produced in separate partonic interactions. At $s_{N N} = 63$ TeV, the pPb cross sections for triple-J $/ ψ$ and triple- $b b$ are $O$ (1--10 mb). In the most energetic cosmic-ray collisions observed on earth, TPS $c c$ -pair cross sections equal the total p-Air inelastic cross section.
↳ hep-phastro-ph.HEhep-exnucl-ex+1EPJC(2018)·32 citations
08
Hyperon single-particle potentials from QCD on lattice
Takashi Inoue · for HAL QCD Collaboration
We study single-particle potential of hyperons in nuclear medium starting from QCD. First we carry out lattice QCD numerical simulation to extract baryon-baryon interactions from QCD by means of the HAL QCD method. We employ a full QCD gauge configuration ensemble at almost physical point so that hadron masses are nearly physical, e.g. pion mass is 146 MeV, kaon mass is 525 MeV, and nucleon mass is 956 MeV. Then, with some simplifications, we apply the obtained hyperon interactions to the Brueckner-Hartree-Fock theory and calculate single-particle potential of hyperons in nuclear medium $U_{Y} (ρ, k)$ . For the symmetric nuclear matter at the normal nuclear matter density, we obtain $U_{Λ} (ρ_{0}, 0) = - 33$ MeV, $U_{Σ} (ρ_{0}, 0) = + 11$ MeV, and $U_{Ξ} (ρ_{0}, 0) = - 6$ MeV. These results are qualitatively compatible with values suggested from experiments. This success is remarkable and encouraging because we are trying to reveal nature of baryon-baryon interactions starting from QCD, and this agreement proves that our approach is essentially correct.
↳ hep-lathep-phnucl-exnucl-thPoS(2016)·24 citations
09
Different pole structures in line shapes of the $X (3872)$
Xian-Wei Kang🇪🇸 · J. A. Oller🇪🇸
We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective-range because it can also handle with a near-threshold zero in the $D^{0} D ˉ^{* 0}$ $S$ -wave. In terms of it we analyze the CDF data on inclusive $p p ˉ$ scattering to $J / ψ π^{+} π^{-}$ , and the Belle and BaBar data on $B$ decays to $K J / ψ π^{+} π^{-}$ and $K D D ˉ^{* 0}$ around the $D^{0} D ˉ^{* 0}$ threshold. It is shown that data can be reproduced with similar quality for the $X (3872)$ being a bound {\it and/or} a virtual state. We also find that the $X (3872)$ might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small $D^{* 0}$ width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the $D^{* 0}$ width itself. The $X (3872)$ compositeness coefficient in $D^{0} D ˉ^{* 0}$ ranges from nearly 0 up to 1 in the different scenarios.
↳ hep-phhep-exnucl-thEPJC(2017)·104 citations
10
Effective field theories for quantum chromo- and electrodynamics
Ou Z. Labun🇺🇸
In this dissertation, I introduce the principles and methods of effective field theory and describe my work in three EFTs: First, in the perturbative QCD region, I use soft collinear effective theory (SCET) to prove that strong interaction soft radiation is universal and to increase the QCD accuracy to next-to-next-tonext- to leading logarithm order for new particle searches in hadron colliders. I also compute a new class of non-perturbative, large logarithmic enhancement arising near the elastic limits of deep inelastic scattering and Drell-Yan processes. Second, in the QCD confinement region, I use heavy hadron chiral perturbation theory to study near-threshold enhancements in the scattering of $D$ and $π$ mesons near the threshold for the excited $D$ -meson state, $D^{*}$ , as well as in the scattering of $D$ and $D^{*}$ mesons near the threshold for the exotic hadron X(3872). This work provides a clear picture of the hadronic molecule X(3872) and more profound understanding of the nuclear force between hadrons. Finally, inspired by SCET, I construct a new electron-laser effective field theory to describe highly-relativistic electrons traveling in strong laser fields, extract the universal distribution of electrons in strong electromagnetic backgrounds and its evolution in energy from the separated momentum scales of emitted photons and classical radiation, and predict the rate of wide angle photon emission. I conclude with limitations of EFT methods and some perspectives on what new work may be achieved with these EFTs.
↳ hep-phnucl-th1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Triple parton scatterings in proton-nucleus collisions at high energies

Hyperon single-particle potentials from QCD on lattice

Different pole structures in line shapes of the X(3872)

Effective field theories for quantum chromo- and electrodynamics

Affiliations

Different pole structures in line shapes of the $X (3872)$