Nuclear Theory·nucl-th

Friday·November 17, 2017

10 papers—4 primary·6 cross-listed

05
[Submitted on 16 Nov 2017] (cross-list from hep-lat)
A complex path around the sign problem
Paulo F. Bedaque🇺🇸
We review recent attempts at dealing with the sign problem in Monte Carlo calculations by deforming the region of integration in the path integral from real to complex fields. We discuss the theoretical foundations, the algorithmic issues and present some results for low dimensional field theories in both imaginary and real time.
Comments:
Write up of the talk delivered al Lattice 2017
Subjects:
High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1711.05868 [pdf]
EPJ Web Conf.(2018)·25 citations
06
[Submitted on 16 Nov 2017] (cross-list from hep-lat)
$S U (2 N_{F})$ symmetry of confinement in QCD and its observation at high temperature
L. Ya. Glozman🇦🇹
In this talk we first overview lattice results that have led to the observation of new SU(2)_{CS} and SU(2N_F) symmetries upon artificial truncation of the near-zero modes of the Dirac operator at zero temperature and at high temperature without any truncation. These symmetries are larger than the chiral symmetry of the QCD Lagrangian and contain chiral symmetries SU(N_F)_L \times SU(N_F)_R and U(1)_A as subgroups. In addition to the standard chiral transformations the SU(2)_{CS} and SU(2N_F) transformations mix the right- and left-handed components of the quark fields. It is a symmetry of the confining chromo-electric interaction while the chromo-magnetic interaction manifestly breaks it. Emergence of these symmetries upon truncation of the near-zero modes of the Dirac operator at T=0 means that all effects of the chromo-magnetic interaction are located exclusively in the near-zero modes, while confining chromo-electric interaction is distributed among all modes. Appearance of these symmetries at high T, where the temperature suppresses the near-zero modes, has radical implications because these symmetries are incompatible with the asymptotically free deconfined quarks at increasing temperature. The elementary objects in the high-temperature phase of QCD should be quarks bound by the pure chromo-electric field that is not accompanied by the chromo-magnetic effects.
Comments:
11 pages, talk presented at 6th International Conference on New Frontiers in Physics, 18.08 - 26.08, 2017, Crete
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1711.06112 [pdf]
EPJ Web Conf.(2018)·2 citations
07
[Submitted on 16 Nov 2017] (cross-list from hep-ph)
Double heavy tri-hadron bound state via delocalized $π$ bond
Li Ma🇩🇪 · Qian Wang🇩🇪 · Ulf-G. Meißner🇩🇪
The number of exotic candidates which are beyond the conventional quark model has grown dramatically during the last decades. Some of them could be viewed as analogues of the deuteron. Similarly, the existence of the triton indicates that bound states formed by three hadrons could also exist. To illustrate this possibility, we study the $D D^{*} K$ and $B B^{*} K ˉ$ systems by using the Born-Oppenheimer Approximation. To leading order, only one-pion exchange potentials are considered, which means that the three constitutes share one virtual pion. That is similar to the role of the delocalized $π$ bond for the formation of Benzene in chemistry. After solving the Schrödinger equation, we find two three-body $D D^{*} K$ and $B B^{*} K ˉ$ bound states with masses $4317.9 2_{- 4.32}^{+ 3.66} MeV$ and $11013.6 5_{- 8.84}^{+ 8.49} MeV$ , respectively. The masses of their $D D ˉ^{*} K$ and $B B ˉ^{*} K ˉ$ analogues are $4317.9 2_{- 6.55}^{+ 6.13} MeV$ and $11013.6 5_{- 9.02}^{+ 8.68} MeV$ . From the experimental side, the $D D ˉ^{*} K$ bound state could be found by analyzing the current world data of the $B \to J / ψ π π K$ process by focusing on the $J / ψ π K$ channel. Its confirmation could also help to understand the formation of kaonic nuclei in nuclear physics.
Comments:
5 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.06143 [pdf]
CPC(2019)·35 citations
08
[Submitted on 16 Nov 2017] (cross-list from hep-ph)
Can one ever prove that neutrinos are Dirac particles?
Martin Hirsch🇪🇸 · Rahul Srivastava🇪🇸 · José W. F. Valle🇪🇸
According to the "Black Box" theorem the experimental confirmation of neutrinoless double beta decay ( $0 ν 2 β$ ) would imply that at least one of the neutrinos is a Majorana particle. However, a null $0 ν 2 β$ signal cannot decide the nature of neutrinos, as it can be suppressed even for Majorana neutrinos. In this letter we argue that if the null $0 ν 2 β$ decay signal is accompanied by a $0 ν 4 β$ quadruple beta decay signal, then at least one neutrino should be a Dirac particle. This argument holds irrespective of the underlying processes leading to such decays.
Comments:
5 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1711.06181 [pdf]
PLB(2018)·57 citations
09
[Submitted on 16 Nov 2017] (cross-list from astro-ph.HE)
Holographic compact stars meet gravitational wave constraints
Eemeli Annala🇫🇮 · Christian Ecker🇦🇹 · Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · David Rodríguez Fernández🇪🇸 · Aleksi Vuorinen🇫🇮
We investigate a simple holographic model for cold and dense deconfined QCD matter consisting of three quark flavors. Varying the single free parameter of the model and utilizing a Chiral Effective Theory equation of state (EoS) for nuclear matter, we find four different compact star solutions: traditional neutron stars, strange quark stars, as well as two non-standard solutions we refer to as hybrid stars of the second and third kind (HS2 and HS3). The HS2s are composed of a nuclear matter core and a crust made of stable strange quark matter, while the HS3s have both a quark mantle and a nuclear crust on top of a nuclear matter core. For all types of stars constructed, we determine not only their mass-radius relations, but also tidal deformabilities, Love numbers, as well as moments of inertia and the mass distribution. We find that there exists a range of parameter values in our model, for which the novel hybrid stars have properties in very good agreement with all existing bounds on the stationary properties of compact stars. In particular, the tidal deformabilities of these solutions are smaller than those of ordinary neutron stars of the same mass, implying that they provide an excellent fit to the recent gravitational wave data GW170817 of LIGO and Virgo. The assumptions underlying the viability of the different star types, in particular those corresponding to absolutely stable quark matter, are finally discussed at some length.
Comments:
34 pages, 6 figures; v3: version accepted for publication at JHEP
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1711.06244 [pdf]
JHEP(2018)·74 citations
10
[Submitted on 16 Nov 2017] (cross-list from hep-ph)
Effect of the chromo-electromagnetic field fluctuations on heavy quark propagation at the LHC energies
Ashik Ikbal Sheikh🇮🇳 · Zubayer Ahammed🇮🇳 · Prashant Shukla🇮🇳 · Munshi G. Mustafa🇮🇳
We consider the effect of the chromo-electromagnetic field fluctuations in addition to the collisional as well as the radiative energy loss suffered by heavy quarks while propagating through the hot and densed deconfined medium of quarks and gluons created in relativistic heavy ion collisions. The chromo-electromagnetic field fluctuations play an important role as it leads to an energy gain of heavy quarks of all momentum, significantly effective at the lower momentum region. With this, we have computed, for the first time, the nuclear modification factor (R_{AA}) of heavy mesons, viz., D-mesons and B-mesons and compared with the those experimental measurements in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV and \sqrt{s_{NN}} = 5.02 TeV by the CMS and ALICE experiments at the LHC. Our results are found to be in very good agreement with those available data measured by CMS and ALICE experiments.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.06245 [pdf]
PRC(2018)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE

A complex path around the sign problem

SU(2NF​) symmetry of confinement in QCD and its observation at high temperature

Double heavy tri-hadron bound state via delocalized π bond

Can one ever prove that neutrinos are Dirac particles?

Holographic compact stars meet gravitational wave constraints

Effect of the chromo-electromagnetic field fluctuations on heavy quark propagation at the LHC energies

Affiliations

$S U (2 N_{F})$ symmetry of confinement in QCD and its observation at high temperature

Double heavy tri-hadron bound state via delocalized $π$ bond