Nuclear Theory·nucl-th

Tuesday·October 22, 2019

11 papers—8 primary·3 cross-listed

09
Renormalization and Matching for the Collins-Soper Kernel from Lattice QCD
Markus A. Ebert🇺🇸 · Iain W. Stewart🇺🇸 · Yong Zhao🇺🇸
The Collins-Soper kernel, which governs the energy evolution of transverse-momentum dependent parton distribution functions (TMDPDFs), is required to accurately predict Drell-Yan like processes at small transverse momentum, and is a key ingredient for extracting TMDPDFs from experiment. Earlier we proposed a method to calculate this kernel from ratios of the so-called quasi-TMDPDFs determined with lattice QCD, which are defined as hadronic matrix elements of staple-shaped Euclidean Wilson line operators. Here we provide the one-loop renormalization of these operators in a regularization-independent momentum subtraction (RI $^{'}$ /MOM) scheme, as well as the conversion factor from the RI $^{'}$ /MOM-renormalized quasi-TMDPDF to the $MS$ scheme. We also propose a procedure for calculating the Collins-Soper kernel directly from position space correlators, which simplifies the lattice determination.
↳ hep-phhep-latnucl-thJHEP(2020)·79 citations
10
High Energy Hadron Production, Self-Organized Criticality and Absorbing State Phase Transition
P.Castorina🇮🇹 · H.Satz🇩🇪
In high energy nuclear collisions, production rates of light nuclei agree with the predictions of an ideal gas at a temperature $T = 155 \pm 10$ MeV. In an equilibrium hadronic medium of this temperature, light nuclei cannot survive. In this contribution, we suggest that the observed behavior is due to an evolution in global non-equilibrium, leading to self-organized criticality and to hadron formation as an absorbing state phase transition for color degrees of freedom. At the confinement point, the initial quark-gluon medium becomes quenched by the vacuum, breaking up into all allowed free hadronic and nuclear mass states, without (or with a very short-live) subsequent formation of thermal hadronic medium.
↳ hep-phnucl-thSpringer Proc.Phys.(2020)·1 citation
11
Feasibility study of the $K^{+} d \to K^{0} pp$ reaction for the " $Θ^{+}$ " pentaquark
Takayasu Sekihara🇯🇵 · Hyun-Chul Kim🇯🇵 · Atsushi Hosaka🇯🇵
We investigate theoretically the $K^{0} p$ invariant mass spectrum of the $K^{+} d \to K^{0} pp$ reaction and scrutinize how the signal of the " $Θ^{+}$ " pentaquark, if it exists, emerges in the $K^{0} p$ spectrum. The most prominent advantage of this reaction is that we can clearly judge whether the " $Θ^{+}$ " exists or not as a direct-formation production without significant backgrounds, in contrast to other reactions such as photoproduction and $π$ -induced productions. We show that while the impulse or single-step scattering process can cover the " $Θ^{+}$ " energy region with an initial kaon momentum $k_{lab} \approx 0.40 GeV / c$ in the laboratory frame, the contributions from double-step processes may have a potential possibility to reach the " $Θ^{+}$ " energy region with a higher kaon momentum $k_{lab} \sim 1 GeV / c$ . Assuming that the full decay width of the " $Θ^{+}$ " is around $0.5 MeV$ , we predict that the magnitude of the peak corresponding to the " $Θ^{+}$ " is around a few hundred $μ b$ to $1 mb$ with the momentum of the kaon beam $k_{lab} \approx 0.40 GeV / c$ while it is around $≲ 1 μ b$ with $k_{lab} \approx 0.85 GeV / c$ . Thus, the " $Θ^{+}$ " peak is more likely to be seen at $k_{lab} \approx 0.40 GeV / c$ than at $k_{lab} \approx 0.85 GeV / c$ .
↳ hep-phhep-exnucl-exnucl-thPTEP(2020)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

Renormalization and Matching for the Collins-Soper Kernel from Lattice QCD

High Energy Hadron Production, Self-Organized Criticality and Absorbing State Phase Transition

Feasibility study of the K+d→K0pp reaction for the "Θ+" pentaquark

Affiliations

Feasibility study of the $K^{+} d \to K^{0} pp$ reaction for the " $Θ^{+}$ " pentaquark