Bulletin of the American Physical Society
APS April Meeting 2020
Volume 65, Number 2
Saturday–Tuesday, April 18–21, 2020; Washington D.C.
Session L16: Theoretical Approaches in Hadronic PhysicsLive

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Sponsoring Units: GHP Chair: Ramona Vogt, Lawrence Livermore National Lab Room: Virginia C 
Sunday, April 19, 2020 3:30PM  3:42PM Live 
L16.00001: Studies of Heavy Quarks and NRQCD at EIC Daniel Boer The U.S.based ElectronIon Collider (EIC) offers many opportunities to investigate heavy quark production. This talk will focus on the use of transverse momentum spectra in open heavy quark production and in quarkonium production to study not only the transverse momentum dependent and spin dependent gluon distributions but also the process of quarkonium production and its description in the NRQCD framework. A new possibility to extract currently poorly known color octet NRQCD Long Distance Matrix Elements from EIC observables will be the main focus of this talk. [Preview Abstract] 
Sunday, April 19, 2020 3:42PM  3:54PM Live 
L16.00002: Loop, String, and Hadron Dynamics in SU(2) Hamiltonian Lattice Gauge Theories Indrakshi Raychowdhury, Jesse R Stryker The question of how to efficiently formulate Hamiltonian gauge theories is experiencing renewed interest due to advances in building quantum simulation platforms. We introduce a reformulation of SU$(2)$ Hamiltonian lattice gauge theory—a loopstringhadron (LSH) formulation—that describes dynamics directly in terms of its loop, string, and hadron degrees of freedom, while alleviating several disadvantages of quantumsimulating the KogutSusskind formulation. This LSH formulation transcends the local loop formulation of $d + 1$dimensional lattice gauge theories by incorporating staggered quarks, furnishing the algebra of gaugesinglet operators, and being used to reconstruct dynamics between states that have Gauss’s law built in to them. LSH operators are then factored into products of “normalized” ladder operators and diagonal matrices, priming them for classical or quantum information processing. The LSH formalism makes little use of structures specific to SU$(2)$ and its conceptual clarity makes it an attractive approach to apply to other nonAbelian groups like SU$(3)$. [Preview Abstract] 
Sunday, April 19, 2020 3:54PM  4:06PM Live 
L16.00003: Helicity at Small $x$: Bringing Back the Quarks Yossathorn Tawabutr, Yuri Kovchegov We find the small$x$ asymptotics of the quark helicity distribution in the large$N_{c}${\&}$N_{f}$ limit by numerically solving small$x$ evolution equations derived in earlier works, where $N_{c}$ is the number of quark colors and $N_{f}$ is the number of quark flavors. Previously, those evolution equations were solved only in the large$N_{c}$ limit. We find that $\Delta q$ oscillates as a function of $\ln {(1/x)}$ at small $x$, with the oscillation frequency being dependent on the number of quark flavors, $N_{f}$. Our result may account for the apparent oscillation in the strange quark helicity distribution $\Delta s$ as a function of Bjorken $x$. For $N_{f}=0$, these oscillations disappear; this is why they were not seen in the earlier large$N_{c}$ studies. Our work presents the most precise theoretical determination of the small$x$ asymptotics of the quark helicity distribution based on the Wilson line approach to small$x$ evolution.~When combined with the future EIC data, our approach should allow for a precise determination of the amount of the proton spin coming from small$x$ partons, thus contributing to the resolution of the proton spin puzzle. [Preview Abstract] 
Sunday, April 19, 2020 4:06PM  4:18PM Live 
L16.00004: Helicitydependent generalization of the McLerranVenugopalan model Florian Cougoulic, Yuri Kovchegov The smallx evolution equation for the quark and gluon helicity distribution have been recently written in the framework of the JalilianMarianIancuMcLerranWeigertLeonidovKovner (JIMWLK) functional evolution equation. Those equations will be useful for numerical evaluation in order to estimate the asymptotic behaviors beyond previously known result in the large Nclimit. This will give us some new insight of the smallx dependence of those distributions in the hope of better understanding the proton spin puzzle. In order to solve those equations, it is necessary to provide an initial condition for the target weight functional. For the JIMWLK (unpolarized) case, this initial condition is usually given by the McLerranVenugopalan (MV) model. However, the MVmodel does not describe helicitydependent fields. We derive a generalization of the MVmodel by including helicitydependent fields which are subeikonal compared to the usual eikonal background field of the MVmodel. The subeikonal fields are generated by diagonal and nondiagonal (in color and flavor spaces) source operators acting on the nucleus state, and the source’s distributions are found to be Gaussian, as in the MVmodel. [Preview Abstract] 
Sunday, April 19, 2020 4:18PM  4:30PM 
L16.00005: Transverse Force Tomography Matthias Burkardt While twist2 GPDs allow for a determination of the distribution of partons on the transverse plane, twist3 GPDs contain quarkgluon correlations that provide information about the average transverse color Lorentz force acting on quarks. As an example, we use the nonforward generalization of $g_T(x)$, to illustrate how twist3 GPDs can provide transverse position information about that force. [Preview Abstract] 
Sunday, April 19, 2020 4:30PM  4:42PM 
L16.00006: $K(1460)$ resonance as the kaonic $KK\bar{K}$ system Roman Kezerashvili, Igor Filikhin, Vladimir Suslov, Shalva Tsiklauri, Branislav Vlahovic The $K(1460)$ pseoudoscalar resonance is studied within a non relativistic potential threebody kaonic $KK\bar{K}$ model in the framework of the Faddeev equations in configuration space. We use a singlechannel approach employing two sets of phenomenological $KK$ and $K\bar{K}$ potentials and taking into account the difference of masses of $K$ and $\bar{K}$ kaons. The latter leads to splitting the mass of the $K(1460)$ resonance according to $% K^{0}K^{0}{\bar{K}}^{0}$, $K^{0}K^{+}K^{}$ and $K^{+}{\bar{K}}^{0}K^{0}$, $% K^{+}K^{+}K^{}$ constituent particle states. The effect of the Coulomb force for $K^{0}K^{+}K^{}$ and $K^{+}K^{+}{\bar{K}}^{}$ systems is considered. Results of calculations for the mass of $K(1460)$ vary from 1469.7 to 1459.5 MeV depending on the constituent particles of the $KK\bar{K} $ system and the range of parameters for $KK$ and $K\bar{K}$ potentials. Our results are in reasonable agreement with the SLAC experiment value 1460 MeV [1] and LHCb recent experimental study 1482.40$\pm $3.58$\pm $15.22 MeV [2]. The width of the resonance is around 142 MeV, which is significantly less than the experimental results. [1] G. W. Brandenburg, et al., Phys. Rev. Lett \textbf{36} (1976) 703. [2] R. Aaij et al., Eur. Phys. J. C \textbf{78} (2018) 443. [Preview Abstract] 
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