Altas Energias

Dumitru, Adrian; Giannini, Andre V.; Luzum, Matthew; Nara, Yasushi

Physics Letters B, Volume 784, p. 417-422

Abstract

Horowitz and Kovchegov have derived a kT-factorization formula for particle production at small x which includes running coupling corrections. We perform a first numerical analysis to confront the theory with data on the energy and centrality dependence of particle multiplicities at midrapidity in high-energy p+A (and A+A) collisions. Moreover, we point out a strikingly different dependence of the multiplicity per participant on Npart in p+Pb vs. Pb+Pb collisions at LHC energies, and argue that the observed behavior follows rather naturally from the convolution of the gluon distributions of an asymmetric vs. symmetric projectile and target.

10.1016/j.physletb.2018.08.028

G.De Conto, A.C.B.Machado, J.P.B.C.de Melo

Physics Letters B, Volume 784, 10 September 2018, Pages 255-260

ABSTRACT

In this paper we present an analytic solution for the mass matrix of the CP-even neutral scalars in the minimal 331 model (m331), identifying the Standard Model Higgs boson and its self-interactions, showing that the m331 can automatically reproduce the Higgs potential of the Standard Model. We also present a method to generate numerical solutions for the quarks and leptons masses and mixings that are compatible with the measured masses, the Cabbibo–Kobayashi–Maskawa (CKM) and Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrices. The method employed here to find these solutions can be adapted to other multi-Higgs models.

DOI:10.1016/j.physletb.2018.07.056

Parada T. P. Hutauruk, Yongseok Oh, and K. Tsushima

Phys. Rev. D 98, 013009

ABSTRACT

Impact of the in-medium modified nucleon weak and electromagnetic form factors on the neutrino mean free path in dense matter is studied by considering both the weak and electromagnetic interactions of neutrinos with the constituents of the matter. A relativistic mean field model and the quark-meson coupling model are respectively adopted for the in-medium effective nucleon mass and nucleon form factors. We find that the cross sections of neutrino scattering in cold nuclear medium decrease when the in-medium modifications of the nucleon weak and electromagnetic form factors are taken into account. This reduction results in the enhancement of the neutrino mean free path, in particular at the baryon density of around a few times of the normal nuclear matter density. The enhancement of the neutrino mean free path is estimated to be about 10%–40% compared with the values obtained without the medium modifications of the nucleon form factors, and the enhancement is expected to accelerate the cooling of neutron stars.

DOI:10.1103/PhysRevD.98.013009