Nuclear Theory·nucl-th

Thursday·November 17, 2016

10 papers—5 primary·5 cross-listed

06
[Submitted on 14 Nov 2016] (cross-list from hep-ph)
Cross section line shape of $e^{+} e^{-} \to χ_{c 0} ω$ around the $Y (4260)$ mass region
Martin Cleven🇪🇸 · Qiang Zhao🇨🇳
We demonstrate that the recent measurement of the cross section line shapes of $e^{+} e^{-} \to χ_{c 0} ω$ can be naturally explained by the molecular picture for $Y (4260)$ where the $Y (4260)$ is treated as a hadronic molecule dominated by $D ˉ D_{1} (2420) + c . c .$ This result is consistent with properties extracted for $Y (4260)$ as the $D ˉ D_{1} (2420) + c . c .$ molecular state in other reactions such as $e^{+} e^{-} \to J / ψ π π$ , $h_{c} π π$ , $D ˉ D^{*} π + c . c .$ , and $γ X (3872)$ .
Comments:
6 pages, 2 Figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1611.04408 [pdf]
PLB(2017)·25 citations
07
[Submitted on 15 Nov 2016] (cross-list from hep-ph)
Beyond WIMPs: the Quark (Anti) Nugget Dark Matter
Ariel Zhitnitsky🇨🇦
We review a testable dark matter (DM) model outside of the standard WIMP paradigm. The model is unique in a sense that the observed ratio $Ω_{dark} ≃ Ω_{visible}$ for visible and dark matter densities finds its natural explanation as a result of their common QCD origin when both types of matter (DM and visible) are formed during the QCD transition and both are proportional to single dimensional parameter of the system, $Λ_{QCD}$ . We argue that the charge separation effect also inevitably occurs during the same QCD transition in the presence of the $C P$ odd axion field $a (x)$ . It leads to preferential formation of one species of nuggets on the scales of the visible Universe where the axion field $a (x)$ is coherent. A natural outcome of this preferential evolution is that only one type of the visible baryons (not anti- baryons) remain in the system after the nuggets complete their formation. Unlike conventional WIMP dark matter candidates, the nuggets and anti-nuggets are strongly interacting but macroscopically large objects. The rare events of annihilation of the anti-nuggets with visible matter lead to a number of observable effects. We argue that the relative intensities for a number of measured excesses of emission from the centre of galaxy (covering more than 11 orders of magnitude) are determined by standard and well established physics. At the same time the absolute intensity of emission is determined by a single new fundamental parameter of the theory, the axion mass, $1 0^{- 6} eV ≲ m_{a} ≲ 1 0^{- 3} eV$ . Finally, we comment on implications of these studies for the axion search experiments, including microwave cavity and the Orpheus experiments.
Comments:
contribution to the "Confinement XII" conference, Thessaloniki, Greece, August 2016
Subjects:
High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th)
arXiv:
1611.05042 [pdf]
EPJ Web Conf.(2017)·4 citations
08
[Submitted on 14 Nov 2016] (cross-list from nucl-ex)
Estimation of Stopped Protons at Energies Relevant for a Beam Energy Scan at the BNL Relativistic Heavy-Ion Collider
Dhananjaya Thakur🇮🇳 · Sunil Jakhar🇮🇳 · Prakhar Garg🇮🇳 · Raghunath Sahoo (Indian Institute of Technology Indore, India)🇮🇳
The recent net-proton fluctuation results of the STAR (Solenoidal Tracker At RHIC) experiment from beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) have drawn much attention to exploring the QCD critical point and the nature of deconfinement phase transition. There has been much speculation that the non-monotonic behavior of $κ σ^{2}$ of the produced protons around $s_{NN}$ = 19.6 GeV in the STAR results may be due to the existence of QCD critical point. However, the experimentally measured proton distributions contain protons from heavy resonance decays, from baryon stopping and from direct production processes. These proton distributions are used to estimate the net-proton number fluctuation. Because it is difficult to disentangle the protons from the above-mentioned sources, it is better to devise a method which will account for the directly produced baryons (protons) to study the dynamical fluctuation at different center-of-mass energies. This is because, it is assumed that any associated criticality in the system could affect the particle production mechanism and hence the dynamical fluctuation in various conserved numbers. In the present work, we demonstrate a method to estimate the number of stopped protons at RHIC BES energies for central $0 - 5%$ \auau collisions within STAR acceptance and discuss its implications on the net-proton fluctuation results.
Comments:
7 pages and 6 figures, Same as the published version in Phys. Rev. C
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1611.05078 [pdf]
PRC(2017)·10 citations
09
[Submitted on 16 Nov 2016] (cross-list from nucl-ex)
Rearrangement of valence neutrons in the neutrinoless double- $β$ decay of $^{136}$ Xe
S. V. Szwec🇬🇧 · B. P. Kay🇺🇸 · T. E. Cocolios🇬🇧 · J. P. Entwisle🇬🇧 · S. J. Freeman🇬🇧 · L. P. Gaffney🇬🇧 · V. Guimarães🇧🇷 · F. Hammache🇫🇷 · P. P. McKee🇬🇧 · E. Parr🇬🇧 · C. Portail🇫🇷 · J. P. Schiffer🇺🇸 and 4 other authors
A quantitative description of the change in ground-state neutron occupancies between $^{136}$ Xe and $^{136}$ Ba, the initial and final state in the neutrinoless double- $β$ decay of $^{136}$ Xe, has been extracted from precision measurements of the cross sections of single-neutron adding and -removing reactions. Comparisons are made to recent theoretical calculations of the same properties using various nuclear-structure models. These are the same calculations used to determine the magnitude of the nuclear matrix elements for the process, which at present disagree with each other by factors of 2 or 3. The experimental neutron occupancies show some disagreement with the theoretical calculations.
Comments:
7 pages, 3 figures, 1 table
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1611.05107 [pdf]
PRC(2016)·30 citations
10
[Submitted on 16 Nov 2016] (cross-list from hep-ph)
Phases of dense matter with holographic instantons
Florian Preis🇦🇹 · Andreas Schmitt🇬🇧
We discuss nuclear matter and the transition to quark matter in the decompactified limit of the Sakai-Sugimoto model. Nuclear matter is included through instantons on the flavor branes of the model. Our approximation is based on the flat-space solution, but we allow for a dynamical instanton width and deformation and compute the energetically preferred number of instanton layers in the bulk as a function of the baryon chemical potential. We determine the regions in parameter space where the binding energy of nuclear matter is like in QCD, and compute the phase diagram in the plane of temperature and chemical potential.
Comments:
9 pages, contribution to the proceedings of "XIIth Quark Confinement and the Hadron Spectrum" in Thessaloniki, Greece, Aug 28 - Sep 4, 2016
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1611.05330 [pdf]
EPJ Web Conf.(2017)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE

Cross section line shape of e+e−→χc0​ω around the Y(4260) mass region

Beyond WIMPs: the Quark (Anti) Nugget Dark Matter

Estimation of Stopped Protons at Energies Relevant for a Beam Energy Scan at the BNL Relativistic Heavy-Ion Collider

Rearrangement of valence neutrons in the neutrinoless double-β decay of 136Xe

Phases of dense matter with holographic instantons

Affiliations

Cross section line shape of $e^{+} e^{-} \to χ_{c 0} ω$ around the $Y (4260)$ mass region

Rearrangement of valence neutrons in the neutrinoless double- $β$ decay of $^{136}$ Xe