Nuclear Theory·nucl-th

Thursday·March 22, 2018

14 papers—9 primary·5 cross-listed

10
[Submitted on 20 Mar 2018] (cross-list from hep-ph)
Dynamical Gauge Boson of Hidden Local Symmetry within the Standard Model
Koichi Yamawaki🇯🇵
The Standard Model (SM) Higgs Lagrangian is straightforwardly rewritten into the {\it scale-invariant} nonlinear sigma model $G / H = [S U (2)_{L} \times S U (2)_{R}] / S U (2)_{V} ≃ O (4) / O (3)$ , with the (approximate) scale symmetry realized nonlinearly by the (pseudo) dilaton ( $=$ SM Higgs). It is further gauge equivalent to that having the symmetry $O (4)_{global} \times O (3)_{local}$ , with $O (3)_{local}$ being the Hidden Local Symmetry (HLS). In the large $N$ limit of the scale-invariant version of the Grassmannian model $G / H = O (N) / [O (N - 3) \times O (3)]$ $≃ O (N)_{global} \times [O (N - 3) \times O (3)]_{local}$ , identical to the SM for $N \to 4$ , we show that the kinetic term of the HLS gauge bosons ("SM rho") $ρ_{μ}$ of the $O (3)_{local} ≃ [S U (2)_{V}]_{local}$ are dynamically generated by the nonperturbative dynamics of the SM itself. The dynamical SM rho stabilizes the skyrmion ("SM skyrmion") $X_{s}$ as a dark matter candidate within the SM: The mass $M_{X_{s}} = O (10 GeV)$ consistent with the direct search experiments implies the induced HLS gauge coupling $g_{_{HLS}} = O (1 0^{3})$ , which realizes the relic abundance, $Ω_{X_{s}} h^{2} = O (0.1)$ . If instead $g_{_{HLS}} ≲ 3.5$ ( $M_{ρ} ≲ 1.2$ TeV), the SM rho could be detected with "narrow width" $≲ 100 GeV$ at LHC, having all the " $a = 2$ results" of the generic HLS Lagrangian $L_{A} + a L_{V}$ , i.e., $ρ$ -universality, KSRF relations and the vector meson dominance, independently of " $a$ ". There exists the second order phase phase transition to the unbroken phase having massless $ρ_{μ}$ and massive $π$ (no longer NG bosons), both becoming massless free particles just on the transition point (scale-invariant ultraviolet fixed point).The results readily apply to the 2-flavored QCD as well.
Comments:
52 pages, for readability preliminary formal discussions moved to appendix, some phenomenological comments added, typos corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1803.07271 [pdf]
10 citations
11
[Submitted on 20 Mar 2018] (cross-list from hep-ph)
Photoproduction of light vector mesons in Xe-Xe ultraperipheral collisions at the LHC and the nuclear density of Xe-129
V. Guzey (St. Petersburg, INP and Jyvaskyla U. and Helsinki Inst. of Phys.)🇷🇺 · E. Kryshen🇷🇺 · M. Zhalov (St. Petersburg, INP)🇷🇺
We make predictions for cross sections of $ρ$ and $ϕ$ vector meson photoproduction in ultraperipheral Xe-Xe collisions at $s_{N N} = 5.44$ TeV. Analyzing the momentum transfer distribution of $ρ$ mesons in this process, we explore the feasibility of extracting the nuclear density of $^{129}$ Xe, which is needed in searches for dark matter with Xenon-based detectors.
Comments:
8 pages, 4 figures. Final published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1803.07638 [pdf]
PLB(2018)·9 citations
12
[Submitted on 21 Mar 2018] (cross-list from hep-ph)
Phenomenological study on the decay widths of $Υ (n S) \to d ˉ^{*} (2380) + X$
Chao-Yi Lü🇨🇳 · P. Wang🇨🇳 · Y. B. Dong🇨🇳 · P. N. Shen🇨🇳 · Z. Y. Zhang🇨🇳 · D. M. Li🇨🇳
The decay widths of $Υ (n S)$ $\to$ $d ˉ^{*} (2380) + X$ with $n = 1, 2, 3$ are studied in a phenomenological way. With the help of crossing symmetry, the decay widths are obtained by investigating the imaginary part of the forward scattering amplitudes between $d^{*}$ and $Υ (n S)$ . The wave functions of $d^{*}$ and deuteron obtained in previous studies are used for calculating the amplitude. The interaction between $d^{*}$ ( $d$ ) and $Υ$ is governed by the quark-meson interaction where the coupling constant is determined by fitting the observed widths of $Υ (n S)$ $\to$ $d ˉ + X$ . The numerical results show that the decay widths of $Υ (n S)$ $\to$ $d ˉ^{*} + X$ are about $2 - 10$ times smaller than that of $d ˉ + X$ . The calculated momentum of $d^{*} ˉ$ is in the range $0.3 - 0.8$ GeV. Therefore, it is very likely that one can find $d ˉ^{*} (2380)$ in these semi-inclusive decay processes.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1803.07795 [pdf]
CPC(2018)·4 citations
13
[Submitted on 21 Mar 2018] (cross-list from hep-ph)
Some intriguing aspects of multiparticle production processes
Grzegorz Wilk🇵🇱 · Zbigniew Włodarczyk🇵🇱
Multiparticle production processes provide valuable information about the mechanism of the conversion of the initial energy of projectiles into a number of secondaries by measuring their multiplicity distributions and their distributions in phase space. They therefore serve as a reference point for more involved measurements. Distributions in phase space are usually investigated using the statistical approach, very successful in general but failing in cases of small colliding systems, small multiplicities, and at the edges of the allowed phase space, in which cases the underlying dynamical effects competing with the statistical distributions take over. We discuss an alternative approach, which applies to the whole phase space without detailed knowledge of dynamics. It is based on a modification of the usual statistics by generalizing it to a superstatistical form. We stress particularly the scaling and self-similar properties of such an approach manifesting themselves as the phenomena of the log-periodic oscillations and oscillations of temperature caused by sound waves in hadronic matter. Concerning the multiplicity distributions we discuss in detail the phenomenon of the oscillatory behaviour of the modified combinants apparently observed in experimental data.
Comments:
Review article, to be published in Int. J. Mod. Phys. A (2018), 50 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1803.07832 [pdf]
Int.J.Mod.Phys.A(2018)·26 citations
14
[Submitted on 21 Mar 2018] (cross-list from hep-ph)
The approach to equilibrium of a quarkonium in a quark-gluon plasma
Jean-Paul Blaizot🇫🇷 · Miguel Angel Escobedo🇫🇮
We derive equations of motion for the reduced density matrix of a heavy quarkonium in contact with a quark-gluon plasma in thermal equilibrium. These equations allow in particular a proper treatment of the regime when the temperature of the plasma is comparable to the binding energy of the quarkonium. These equations are used to study how the quarkonium approaches equilibrium with the plasma, and we discuss the corresponding entropy increase, or free energy decrease, depending on the temperature regime. The effect of collisions can be accounted for by the generalization of the imaginary potential introduced in previous studies, and from which collision rates are derived. An important outcome of the present analysis is that this imaginary potential has a sizeable dependence on the energy of the relevant transitions.
Comments:
47 pages, 8 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1803.07996 [pdf]
PRD(2018)·101 citations

Affiliations

first authorsco-authorsvia INSPIRE

Dynamical Gauge Boson of Hidden Local Symmetry within the Standard Model

Photoproduction of light vector mesons in Xe-Xe ultraperipheral collisions at the LHC and the nuclear density of Xe-129

Phenomenological study on the decay widths of Υ(nS)→dˉ∗(2380)+X

Some intriguing aspects of multiparticle production processes

The approach to equilibrium of a quarkonium in a quark-gluon plasma

Affiliations

Phenomenological study on the decay widths of $Υ (n S) \to d ˉ^{*} (2380) + X$