Neutrino emissivity from Goldstone boson decay in magnetized neutron matter

AbstractThe Higgs sector in neutral naturalness models provides a portal to the hidden sectors, and thus measurements of Higgs couplings at current and future colliders play a central role in constraining the parameter space of the model. We investigate a class of neutral naturalness models, in which the Higgs boson is a pseudo-Goldstone boson from the universal SO(N)/SO(N −1) coset structure. Integrating out the radial mode from the spontaneous global symmetry breaking, we obtain various dimension-six operators in the Standard Model effective field theory, and calculate the low energy Higgs effective potential with radiative corrections included. We perform aχ2fit to the Higgs coupling precision measurements at current and future colliders and show that the new physics scale could be explored up to 2.3 (2.4) TeV without (with) the Higgs invisible decay channels at future Higgs factories. The limits are comparable to the indirect constraints obtained via electroweak precision measurements.

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Structure of flavor changing Goldstone boson interactions

Journal of High Energy Physics ◽

10.1007/jhep04(2021)141 ◽

2021 ◽

Vol 2021 (4) ◽

Author(s):

Jin Sun ◽

Yu Cheng ◽

Xiao-Gang He

Keyword(s):

Symmetry Breaking ◽

Model Building ◽

Neutral Current ◽

Goldstone Boson ◽

New Physics ◽

Majorana Neutrino ◽

Neutrino Masses ◽

Type I ◽

Flavor Changing ◽

Flavor Changing Neutral Current

Abstract General flavor changing Goldstone boson (GB) interactions with fermions from a spontaneous global U(1)G symmetry breaking are discussed. This GB may be the Axion, solving the strong QCD CP problem, if there is a QCD anomaly for the assignments of quarks U(1)G charge. Or it may be the Majoron, producing seesaw Majorana neutrino masses by lepton number violation, if the symmetry breaking scale is much higher than the electroweak scale. It may also, in principle, play the roles of Axion and Majoron simultaneously as far as providing solution for the strong CP problem and generating a small Majorana neutrino masses are concerned. Great attentions have been focused on flavor conserving GB interactions. Recently flavor changing Axion and Majoron models have been studied in the hope to find new physics from rare decays in the intensity frontier. In this work, we will provide a systematic model building aspect study for flavor changing neutral current (FCNC) GB interactions in the fermion sectors, or separately in the quark, charged lepton and neutrino sectors and will identify in detail the sources of FCNC interactions in a class of beyond standard model with a spontaneous global U(1)G symmetry breaking. We also provide a general proof of the equivalence of using physical GB components and GB broken generators for calculating GB couplings to two gluons and two photons, and discuss some issues related to spontaneous CP violation models. Besides, we will also provide some details for obtaining FCNC GB interactions in several popular models, such as the Type-I, -II, -III seesaw and Left-Right symmetric models, and point out some special features in these models.

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Superfluid Phonons in Neutron Star Core

Universe ◽

10.3390/universe7010016 ◽

2021 ◽

Vol 7 (1) ◽

pp. 16

Author(s):

Marcello Baldo

Keyword(s):

Neutron Star ◽

Inner Core ◽

Mutual Influence ◽

Collective Excitation ◽

Neutron Matter ◽

Superfluid Phase ◽

S Wave ◽

Spectral Functions ◽

Open Problems ◽

Linear Spectrum

In neutron stars the nuclear asymmetric matter is expected to undergo phase transitions to a superfluid state. According to simple estimates, neutron matter in the inner crust and just below should be in the s-wave superfluid phase, corresponding to the neutron-neutron 1S0 channel. At higher density in the core also the proton component should be superfluid, while in the inner core the neutron matter can be in the 3P2 superfluid phase. Superluidity is believed to be at the basis of the glitches phenomenon and to play a decisive influence on many processes like transport, neutrino emission and cooling, and so on. One of the peculiarity of the superfluid phase is the presence of characteristic collective excitation, the so called ’phonons’, that correspond to smooth modulations of the order parameter and display a linear spectrum at low enough momentum. This paper is a brief review of the different phonons that can appear in Neutron Star superfuid matter and their role in several dynamical processes. Particular emphasis is put on the spectral functions of the different components, that is neutron, protons and electrons, which reveal their mutual influence. The open problems are discussed and indications on the work that remain to be done are given.

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Variational and parquet-diagram calculations for neutron matter. III. S -wave pairing

Physical Review C ◽

10.1103/physrevc.103.035808 ◽

2021 ◽

Vol 103 (3) ◽

Author(s):

E. Krotscheck ◽

J. Wang

Keyword(s):

Neutron Matter ◽

S Wave ◽

Wave Pairing

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Relaxing cosmological neutrino mass bounds with unstable neutrinos

Journal of High Energy Physics ◽

10.1007/jhep12(2020)119 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

Miguel Escudero ◽

Jacobo Lopez-Pavon ◽

Nuria Rius ◽

Stefan Sandner

Keyword(s):

Neutrino Mass ◽

Particle Physics ◽

Goldstone Boson ◽

Mass Scale ◽

Simple Extension ◽

Type I ◽

Mass Generation ◽

Age Of The Universe ◽

Neutrino Mass Models ◽

The Right

Abstract At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (ΛCDM), the Planck collaboration reports ∑mv< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe τν ≲ tU, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ν4 and a Goldstone boson ϕ, in which νi→ ν4ϕ decays can loosen the neutrino mass bounds up to ∑mv ∼ 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)μ−τ flavor symmetry, which are otherwise in tension with the current bound on ∑mv.

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Covariant nucleon electromagnetic form factors from the Goldstone-boson-exchange quark model

Physics Letters B ◽

10.1016/s0370-2693(01)00622-0 ◽

2001 ◽

Vol 511 (1) ◽

pp. 33-39 ◽

Cited By ~ 111

Author(s):

R.F. Wagenbrunn ◽

S. Boffi ◽

W. Klink ◽

W. Plessas ◽

M. Radici

Keyword(s):

Quark Model ◽

Goldstone Boson ◽

Form Factors ◽

Electromagnetic Form Factors ◽

Boson Exchange

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Ferromagnetism in neutron matter and its implication for the neutron star equation of state

10.1063/1.3629525 ◽

2011 ◽

Author(s):

J. P. W. Diener ◽

F. G. Scholtz ◽

Ersin Göğüş ◽

Ünal Ertan ◽

Tomaso Belloni

Keyword(s):

Neutron Star ◽

Equation Of State ◽

Neutron Matter

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VMC CALCULATIONS OF THE GROUND STATE PROPERTIES OF NUCLEAR MATTER

International Journal of Modern Physics E ◽

10.1142/s0218301305003004 ◽

2005 ◽

Vol 14 (02) ◽

pp. 255-267 ◽

Cited By ~ 4

Author(s):

KAAN MANİSA ◽

ÜLFET ATAV ◽

RIZA OGUL

Keyword(s):

Nuclear Matter ◽

Ground State ◽

Nucleon Nucleon ◽

Neutron Matter ◽

Potential Term ◽

Ground State Properties ◽

Dependent Potential ◽

Variational Monte Carlo Method ◽

Kinetic And Potential Energies ◽

Good Agreement

A Variational Monte Carlo method (VMC) is described for the evaluation of the ground state properties of nuclear matter. Equilibrium properties of symmetric nuclear matter and neutron matter are calculated by the described VMC method. The Urbana ν14 potential is used for the nucleon–nucleon interactions in the calculations. Three- and more-body interactions are included as a density dependent potential term. Total, kinetic and potential energies per particle are obtained for nuclear and neutron matter. Pressure values of nuclear and neutron matter are also calculated at various densities. The binding energy of nuclear matter is found to be -16.06 MeV at a saturation density of 0.16 fm -3. The results obtained are in good agreement with those obtained by various authors with different potentials and techniques.

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