Nuclear Theory·nucl-th

Tuesday·April 12, 2022

7 papers—3 primary·4 cross-listed

04
[Submitted on 10 Apr 2022] (cross-list from hep-ph)
Neutron-neutral particle mixing and its observable consequences
Yongliang Hao🇨🇳 · Dongdong Ni🇨🇳
In this work, we explore the mixing between neutron ( $n$ ) and elementary neutral particle ( $η$ ), which violates both the baryon number ( $B$ ) and the lepton number ( $L$ ) by one unit but conserves their difference $(B - L)$ . Such mixing may give rise to non-trivial effects that are different from the Standard Model predictions. We organize our discussions based on two scenarios, roughly depending on whether an interference between oscillation and decay occurs, or whether the new-physics effects associated with the $n$ - $η$ mixing contribute to the absorptive mixing amplitude. If an oscillation process is not accompanied by an interference between oscillation and decay, or the new-physics interactions do not contribute to the absorptive mixing amplitude, such a process can be classified as pure oscillation. Otherwise, it can be classified as impure oscillation. In the scenario of pure oscillation, CP-violation arising from the Majorana phase can manifest itself through the $n$ - $n ˉ$ oscillation process and may lead to observable effects. In the scenario of impure oscillation, we analyze the testable implications on the masses and lifetimes of the mass eigenstates formed as a result of the $n$ - $n ˉ$ oscillation mediated by $η$ . In this scenario, we also suggest a unified interpretation of the neutron lifetime anomaly and the $n$ - $n ˉ$ oscillation measurements based on the $n$ - $η$ mixing. In both scenarios, we present the lower bounds imposed by the experimental searches for $n$ - $n ˉ$ oscillations on the masses of the color multiplet bosons and point out that they could be within the reach of a direct detection at the LHC or future high-energy experiments.
Comments:
18 pages, 6 figures and 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.04713 [pdf]
PRD(2022)·6 citations
05
[Submitted on 11 Apr 2022] (cross-list from hep-lat)
Spurious poles in a finite volume
Jin-Yi Pang🇨🇳 · Martin Ebert🇩🇪 · Hans-Werner Hammer🇩🇪 · Fabian Müller🇩🇪 · Akaki Rusetsky🇩🇪 · Jia-Jun Wu🇨🇳
Using effective-range expansion for the two-body amplitudes may generate spurious sub-threshold poles outside of the convergence range of the expansion. In the infinite volume, the emergence of such poles leads to the inconsistencies in the three-body equations, e.g., to the breakdown of unitarity. We investigate the effect of the spurious poles on the three-body quantization condition in a finite volume and show that it leads to a peculiar dependence of the energy levels on the box size $L$ . Furthermore, within a simple model, it is demonstrated that the procedure for the removal of these poles, which was recently proposed in Ref.[1] in the infinite volume, can be adapted to the finite-volume calculations. The structure of the exact energy levels is reproduced with an accuracy that systematically improves order by order in the EFT expansion.
Comments:
26 pages, 9 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2204.04807 [pdf]
JHEP(2022)·9 citations
06
[Submitted on 11 Apr 2022] (cross-list from hep-lat)
Impact of Dynamical Fermions on Centre Vortex Structure
Derek Leinweber🇦🇺 · James Biddle🇦🇺 · Waseem Kamleh (University of Adelaide)🇦🇺
This presentation examines the centre vortex structure of Monte-Carlo generated gauge-field configurations using modern visualisation techniques. This time, the manner in which light dynamical fermion degrees of freedom impact the centre-vortex structure is explored. Focusing on the thin vortices identified by plaquettes having a non-trivial centre phase, the vortex structure is illustrated through 3D renderings of oriented plaquettes. The impact of light dynamical fermions is not subtle, changing both the density of vortices and the complexity of the vortex structures observed. The role of vortex branching points in full QCD is highlighted in the survey of results presented.
Comments:
9 pages, 5 figures with 4 3D interactive. Proceedings of the 38th International Symposium on Lattice Field Theory (Lattice 2021), 26th - 30th July 2021, Zoom/Gather@Massachusetts Institute of Technology
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2204.04825 [pdf]
PoS(2022)·3 citations
07
[Submitted on 11 Apr 2022] (cross-list from hep-ph)
Chiral spin symmetry and the QCD phase diagram
Leonid Ya. Glozman🇦🇹 · Owe Philipsen🇩🇪 · Robert D. Pisarski🇺🇸
Lattice QCD simulations with chirally symmetric quarks have recently established approximate $S U (2)_{C S}$ and $S U (2 N_{F})$ symmetries of the quantum effective action in a temperature range above the chiral crossover $T_{ch}$ , in which color-electric interactions between quarks dominate the dynamics. We show that such an intermediate temperature range between the chirally broken and plasma regimes is fully consistent with published screening mass spectra, which demonstrate the breakdown of thermal perturbation theory at the crossover between the partonic and the chiral spin symmetric regime at $T_{s} \sim (2 - 3) T_{ch}$ . From the known behavior of screening masses with baryon chemical potential, we deduce qualitatively how this chiral spin symmetric band extends into the QCD phase diagram. In the cold and dense region, we propose parity doubled baryons as possible candidates for chiral spin symmetric matter. This represents a special case of quarkyonic matter with confinement and restored chiral symmetry, and can smoothly transform to quark matter at sufficiently high densities. Finally, we discuss the potential of dilepton spectra to identify such matter forms.
Comments:
12 pages, 6 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2204.05083 [pdf]
EPJA(2022)·59 citations

Affiliations

first authorsco-authorsvia INSPIRE

Neutron-neutral particle mixing and its observable consequences

Spurious poles in a finite volume

Impact of Dynamical Fermions on Centre Vortex Structure

Chiral spin symmetry and the QCD phase diagram

Affiliations