Abstract: We perform calculations for the (B) over bar (0)(s)-> J/psi pi(0)f(0)(980) and (B) over bar (0)(s)-> J/psi pi(0)a(0)(980) reactions, showing that the first is isospin-suppressed while the second is isospin-allowed. The reaction proceeds via a triangle mechanism, with (B) over bar (0)(s)-> J/psi K*(K) over bar +c.c., followed by the decay K*-> K pi and a further fusion of K (K) over bar into the f(0)(980) or a(0)(980). We show that the mechanism develops a singularity around the pi(0)f(0)(980) or pi(0)a(0)(980) invariant mass of 1420 MeV, where the pi(0)f(0) and pi(0)a(0) decay modes are magnified and also the ratio of pi(0)f(0) to pi(0)a(0) production. Using experimental information for the (B) over bar (0)(s)-> J/psi K*(K) over bar +c.c. decay, we are able to obtain absolute values for the reactions studied which fall into the experimentally accessible range. The reactions proposed and the observables evaluated, when contrasted with actual experiments, should be very valuable to obtain information on the nature of the low lying scalar mesons.

Abstract: The possible role of the triangle mechanism in the B- decay into D*(0)pi(-)pi(0)eta and D*(0)pi(-)pi(+)pi(-) is investigated. In this process, the triangle singularity appears from the decay of B- into D*K-0(-) K*(0) followed by the decay of K-*0 into pi(-) K+ and the fusion of the K+ K-, which forms the a(0)(980) or f(0)(980), which finally decay into pi(0)eta or pi(+)pi(-), respectively. The triangle mechanism from the (K) over bar * K (K) over bar loop generates a peak around 1420 MeV in the invariant mass of pi(-) a(0) or pi(-) f(0), and it gives sizable branching fractions, Br(B- -> D*(0)pi(-) a(0); a(0) -> pi(0)eta) = (1.66 +/- 0.45) x 10(-6) and Br(B- -> D*(0)pi(-) f(0); f(0) -> pi(+)pi(-)) = (2.82 +/- 0.75) x 10(-6).

Abstract: We show that the tau(-) decay into f(1)(1285) pi(-)nu(tau) is dominated by a triangle loop mechanism with K*, (K) over bar* and K( or (K) over bar) as internal lines, which manifests a strong enhancement reminiscent of a nearby singularity present in the narrow K* limit and the near (K) over bar* K* threshold of the internal K* propagators. The f1(1285) is then produced by its coupling to the K* (K) over bar and (K) over bar* K which is obtained from a previous model where this resonance was dynamically generated as a molecular K* (K) over bar (or (K) over bar* K) state using the techniques of the chiral unitary approach. We make predictions for the f(1)pi mass distribution which significantly deviates from the phase-space shape, due to the distortion caused by the triangle mechanism and the K* (K) over bar threshold. We find a good agreement with the experimental value within uncertainties for the integrated partial decay width, which is a clear indication of the importance of the triangle mechanism in this decay and supports the dynamical origin of the f(1)(1285) as a K* (K) over bar and (K) over bar* K molecular state.

Abstract: In this paper we discuss SU(5)3 with cyclic symmetry as a possible grand unified theory (GUT). The basic idea of such a tri-unification is that there is a separate SU(5) for each fermion family, with the light Higgs doublet(s) arising from the third family SU(5), providing a basis for charged fermion mass hierarchies. SU(5)3 tri-unification reconciles the idea of gauge non-universality with the idea of gauge coupling unification, opening the possibility to build consistent non-universal descriptions of Nature that are valid all the way up to the scale of grand unification. As a concrete example, we propose a grand unified embedding of the tri-hypercharge model \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{U}}{\left(1\right)}_{Y}<^>{3}$$\end{document} based on an SU(5)3 framework with cyclic symmetry. We discuss a minimal tri-hypercharge example which can account for all the quark and lepton (including neutrino) masses and mixing parameters. We show that it is possible to unify the many gauge couplings into a single gauge coupling associated with the cyclic SU(5)3 gauge group, by assuming minimal multiplet splitting, together with a set of relatively light colour octet scalars. We also study proton decay in this example, and present the predictions for the proton lifetime in the dominant e+pi 0 channel.

Abstract: Measurements of the per-event charged-particle yield as a function of the charged-particle transverse momentum and rapidity are performed using p + Pbcollision data collected by the ATLAS experiment at the LHC at a centre-of-mass energy of root sNN= 5.02 TeV. Charged particles are reconstructed over pseudorapidity |eta| < 2.3and transverse momentum between 0.1GeVand 22GeVin a dataset corresponding to an integrated luminosity of 1 μb(-1). The results are presented in the form of chargedparticle nuclear modification factors, where the p + Pbcharged-particle multiplicities are compared between central and peripheral p + Pbcollisions as well as to charged-particle cross sections measured in ppcollisions. The p + Pbcollision centrality is characterized by the total transverse energy measured in -4.9<eta<-3.1, which is in the direction of the outgoing lead beam. Three different estimations of the number of nucleons participating in the p + Pbcollision are carried out using the Glauber model and two Glauber-Gribov colour-fluctuation extensions to the Glauber model. The values of the nuclear modification factors are found to vary significantly as a function of rapidity and transverse momentum. Abroad peak is observed for all centralities and rapidities in the nuclear modification factors for chargedparticle transverse momentum values around 3GeV. The magnitude of the peak increases for more central collisions as well as rapidity ranges closer to the direction of the outgoing lead nucleus.