Nuclear Theory·nucl-th

Tuesday·February 10, 2015

12 papers—4 primary·8 cross-listed

05
Spectroscopy of doubly-charmed baryons from lattice QCD
M. Padmanath🇦🇹 · Robert G. Edwards🇺🇸 · Nilmani Mathur🇮🇳 · Michael Peardon🇮🇪
We present the ground and excited state spectra of doubly charmed baryons from lattice QCD with dynamical quark fields. Calculations are performed on anisotropic lattices of size 16^3 X 128, with inverse spacing in temporal direction 1/a_t = 5.67(4) GeV and with a pion mass of about 390 MeV. A large set of baryonic operators that respect the symmetries of the lattice yet which retain a memory of their continuum analogues are used. These operators transform as irreducible representations of SU(3) symmetry for flavor, SU(4) symmetry for Dirac spins of quarks and O(3) for spatial symmetry. The distillation method is utilized to generate baryon correlation functions which are analysed using the variational fitting method to extract excited states. The lattice spectra obtained have baryonic states with well-defined total spins up to 7/2 and the pattern of low lying states does not support the diquark picture for doubly charmed baryons. On the contrary the calculated spectra are remarkably similar to the expectations from models with an SU(6)X O(3) symmetry. Various spin dependent energy splittings between the extracted states are also evaluated.
↳ hep-lathep-phnucl-thPRD(2015)·95 citations
06
Gauge Invariance and Holographic Renormalization
Keun-Young Kim🇰🇷 · Kyung Kiu Kim🇰🇷 · Yunseok Seo🇰🇷 · Sang-Jin Sin🇰🇷
We study the gauge invariance of physical observables in holographic theories under the local diffeomorphism. We find that gauge invariance is intimately related to the holographic renormalisation: the local counter terms defined in the boundary cancel most of gauge dependences of the on-shell action as well as the divergences. There is a mismatch in the degrees of freedom between the bulk theory and the boundary one. We resolve this problem by noticing that there is a residual gauge symmetry(RGS). By extending the RGS such that it satisfies infalling boundary condition at the horizon, we can understand the problem in the context of general holographic embedding of a global symmetry at the boundary into the local gauge symmetry in the bulk.
↳ hep-thcond-mat.str-elnucl-thPLB(2015)·16 citations
07
Back-to-back isolated photon-quarkonium production at the LHC and the transverse-momentum-dependent distributions of the gluons in the proton
J.P. Lansberg🇫🇷
The study of a quasi back-to-back isolated pair made of a heavy quarkonium, such as a J/psi or a Upsilon, and a photon produced in proton-proton collisions at the LHC, is probably the optimal way to get right away a first experimental determination of two gluon transverse-momentum-dependent distributions (TMDs) in an unpolarized proton, f1^g and h1^perp,g the latter giving the distribution of linearly polarized gluons. To substantiate this, we calculate the transverse-momentum-dependent effects that arise in the process under study and discuss the feasibility of their measurements.
↳ hep-phhep-exnucl-exnucl-thInt.J.Mod.Phys.Conf.Ser.(2016)·8 citations
08
The electric dipole moment of the neutron from 2+1 flavor lattice QCD
F.-K. Guo🇩🇪 · R. Horsley🇬🇧 · U.-G. Meissner🇩🇪 · Y. Nakamura🇯🇵 · H. Perlt🇩🇪 · P. E. L. Rakow🇬🇧 · G. Schierholz🇩🇪 · A. Schiller🇩🇪 · J. M. Zanotti🇦🇺
We compute the electric dipole moment d_n of the neutron from a fully dynamical simulation of lattice QCD with 2+1 flavors of clover fermions and nonvanishing theta term. The latter is rotated into the pseudoscalar density in the fermionic action using the axial anomaly. To make the action real, the vacuum angle theta is taken to be purely imaginary. The physical value of d_n is obtained by analytic continuation. We find d_n = -3.8(2)(9) x 10^{-16} [theta e cm], which, when combined with the experimental limit on d_n, leads to the upper bound theta < 7.6 x 10^{-11}.
↳ hep-lathep-phnucl-thPRL(2015)·123 citations
09
Direct numerical solution of the coordinate space Balitsky-Kovchegov equation at next to leading order
T. Lappi🇫🇮 · H. Mäntysaari🇫🇮
We present the first numerical solution to the next to leading order Balitsky-Kovchegov (BK) equation in coordinate space in the large- $N_{c}$ limit. In addition to the dipole operator we also solve the evolution of the "conformal dipole" for which the conformal invariance breaking double logarithmic term is absent from the evolution equation. The NLO corrections are shown to slow down the evolution. We show that the solution depends strongly on the details of the initial condition, and that the solution to the equation is not positive definite with all initial conditions relevant for phenomenological applications.
↳ hep-phnucl-thPRD(2015)·130 citations
10
Inhomogeneous quark condensate in compressed skyrmion matter
Masayasu Harada🇯🇵 · Hyun Kyu Lee🇰🇷 · Yong-Liang Ma🇨🇳 · Mannque Rho🇰🇷
The inhomogeneous quark condensate, responsible for dynamical chiral symmetry breaking in cold nuclear matter, is studied by putting skyrmions onto the face-centered cubic crystal and treating the skyrmion matter as nuclear matter. By varying the crystal size, we explore the effect of density on the local structure of the quark-antiquark condensate. By endowing the light vector mesons $ρ$ and $ω$ with hidden local symmetry and incorporating a scalar meson as a dilaton of spontaneously broken scale symmetry, we uncover the intricate interplay of heavy mesons in the local structure of the quark condensate in dense baryonic matter described in terms of skyrmion crystal. It is found that the inhomogeneous quark density persists to as high a density as $\sim 4$ times nuclear matter density. The difference between the result from the present approach and that from the chiral density wave ansatz is also discussed.
↳ hep-phnucl-thPRD(2015)·20 citations
11
Anisotropic Flow and Jet Quenching in Relativistic Nuclear Collisions
Guang-You Qin🇨🇳
The exploration of the strong-interaction matter under extreme conditions is one of the main goals of relativistic heavy-ion collisions. We provide some of the main results on the novel properties of quark-gluon plasma, with particular focus given to the strong collectivity and the color opaqueness exhibited by such hot and dense matter produced in high-energy nuclear collisions at RHIC and the LHC.
↳ hep-phnucl-exnucl-thIJMPE(2015)·10 citations
12
On the infrared behavior of the shear spectral function in hot Yang-Mills theory
Aleksi Vuorinen🇫🇮 · Yan Zhu🇪🇸
We revisit the determination of the two-loop spectral function in the shear channel of hot Yang-Mills theory. Correcting a technical error in an earlier computation and extending the result with a leading order Hard Thermal Loop resummation is seen to improve the infrared behavior of the quantity significantly. This makes it possible to straightforwardly use the result in the corresponding imaginary time correlator and the shear sum rule.
↳ hep-phhep-latnucl-thJHEP(2015)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE