A mechanical model of Brownian motion for one massive particle including low energy light particles in dimension d ≥ 3

We provide a connection between Brownian motion and a classical Newton mechanical system in dimension d ≥ 3 {d\geq 3} . This paper is an extension of [S. Liang, A mechanical model of Brownian motion for one massive particle including slow light particles, J. Stat. Phys. 170 2018, 2, 286–350]. Precisely, we consider a system of one massive particle interacting with an ideal gas, evolved according to non-random Newton mechanical principles, via interaction potentials, without any assumption requiring that the initial energies of the environmental particles should be restricted to be “high enough”. We prove that, as in the high-dimensional case, the position/velocity process of the massive particle converges to a diffusion process when the mass of the environmental particles converges to 0, while the density and the velocities of them go to infinity.

Estimation Pre-Equilibrium Particle and Angular Distribution Spectra for the Neutrons Induce Nuclear Reactions on 90Zr Nuclei by using (FKK) Model

Particles pre - equilibrium spectra and angular distribution are calculated by usingFeshbach-Kerman- Koonin (FKK) model with PRECO-2006 code. The angular distribution of the nuclei of nuclear reactions between the nucleus of a target (90Zr) and the tapline of light particles wascalculated by using reactions of the multistep compound (MSC) and of multistep direct (MSD).Isospin, the finite well depth, and shell effects are considered. Byusing [(_40^90)〖Zr〗_50 ] as target material the cross section of [90Zr(n,n)90Zr], [90Zr(n,p)90Y], [90Zr(n,D)89Y], [90Zr(n,T)88Y], [90Zr(n,3He)88Sr] and [90Zr(n,4He)87Sr] reactions were estimated. Values of cross sections estimated are 550, 371, 16.3, 4.55, 0.271 and 2.35 mb/MeV respectively. Also the angular distribution of same nuclear reactions were estimated, and the values of angular distribution are 850, 392, 4.55, 4.55,0.27 and 2.35mb/sr.MeV respectively.

On the Interpretation of Nonresonant Phenomena at Colliders

With null results in resonance searches at the LHC, the physics potential focus is now shifting towards the interpretation of nonresonant phenomena. An example of such shift is the increased popularity of the EFT programme. We can embark on such programme owing to the good integrated luminosity and an excellent understanding of the detectors, which will allow these searches to become more intense as the LHC continues. In this paper, we provide a framework to perform this interpretation in terms of a diverse set of scenarios, including (1) generic heavy new physics described at low energies in terms of a derivative expansion, such as in the EFT approach; (2) very light particles with derivative couplings, such as axions or other light pseudo-Goldstone bosons; and (3) the effect of a quasicontinuum of resonances, which can come from a number of strongly coupled theories, extradimensional models, clockwork set-ups, and their deconstructed cousins. These scenarios are not equivalent despite all nonresonance, although the matching among some of them is possible, and we provide it in this paper.

Tachyon – A Non-Existent Particle

In a 1967 paper [1], G. Feinberg conjectured about the possibility of “faster-than-light” particles. In the current note we prove his conjecture to be false by showing that he missed several key counter-arguments to their existence. We explain why the existence of tachyons contradicts both relativistic kinematics and relativistic dynamics. Our paper is divided in two sections: the kinematic counter-arguments and the dynamics counter-arguments.

A nuclear spin and spatial symmetry-adapted full quantum method for light particles inside carbon nanotubes: clusters of 3He, 4He, and para-H2

A new nuclear spin and spatial symmetry-adapted full quantum method for light fermionic and bosonic particles under cylindrical carbon nanotube confinement.

Supernova Muons: New Constraints on Z′ Bosons, Axions and ALPs

New light particles produced in supernovae can lead to additional energy loss and a consequent deficit in neutrino production in conflict with the neutrinos observed from Supernova 1987A (SN1987A). Contrary to the majority of previous SN1987A studies, we examine the impact of Z′ bosons, axions, and axion-like particles (ALPs) interacting with the muons produced in SN1987A. For the first time, we find constraints on generic Z′ bosons coupled to muons, and apply our results to particle models including gauged Lμ−Lτ number, $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ , and gauged B − L number, U(1)B−L. We constrain Z′ bosons with masses up to about 250 − 500 MeV, and down to about 10−9 in Z′-muon coupling. We also extend previous work on axion-muon couplings by examining the importance of loop-level interactions, as well as performing calculations over a wider range of axion masses. We constrain muon-coupled axions from arbitrarily low masses up to about 200 − 500 MeV, with bounds extending down to axion-muon couplings of approximately 10−8 GeV−1. We conclude that supernovae broadly provide a sensitive probe of new lightly-coupled particles interacting with muons.