scholarly journals Natural relaxation

2016 ◽  
Vol 31 (39) ◽  
pp. 1650215 ◽  
Author(s):  
Luca Marzola ◽  
Martti Raidal
Keyword(s):  
Hadron Collider ◽  
Planck Scale ◽  
Vacuum State ◽  
Relaxation Mechanism ◽  
Mass Scale ◽  
Boson Mass ◽  
Inflationary Cosmology ◽  
Vacuum Stability ◽  
Seesaw Mechanism ◽  
The One

Motivated by natural inflation, we propose a relaxation mechanism consistent with inflationary cosmology that explains the hierarchy between the electroweak scale and Planck scale. This scenario is based on a selection mechanism that identifies the low-scale dynamics as the one that is screened from UV physics. The scenario also predicts the near-criticality and metastability of the Standard Model (SM) vacuum state, explaining the Higgs boson mass observed at the Large Hadron Collider (LHC). Once Majorana right-handed neutrinos are introduced to provide a viable reheating channel, our framework yields a corresponding mass scale that allows for the seesaw mechanism as well as for standard thermal leptogenesis. We argue that considering singlet scalar dark matter extensions of the proposed scenario could solve the vacuum stability problem and discuss how the cosmological constant problem is possibly addressed.

scholarly journals TRIBIMAXIMAL MIXING IN NEUTRINO MASS MATRICES WITH TEXTURE ZEROS OR VANISHING MINORS

2011 ◽  
Vol 26 (07) ◽  
pp. 501-514 ◽  
Author(s):  
S. DEV ◽  
SHIVANI GUPTA ◽  
RADHA RAMAN GAUTAM
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Mass Scale ◽  
Neutrino Mass Matrix ◽  
Seesaw Mechanism ◽  
Majorana Mass ◽  
Absolute Mass ◽  
Mass Matrices ◽  
The One ◽  
The Right

We study the existence of one/two texture zeros or one/two vanishing minors in the neutrino mass matrix with μτ symmetry. In the basis where the charged lepton mass matrix and the Dirac neutrino mass matrix are diagonal, the one/two zeros or one/two vanishing minors on the right-handed Majorana mass matrix having μτ symmetry will propagate via seesaw mechanism as one/two vanishing minors or one/two texture zeros in the neutrino mass matrix with μτ symmetry respectively. It is found that only five such texture structures of the neutrino mass matrix are phenomenologically viable. For tribimaximal mixing, these texture structures reduce the number of free parameters to one. Interesting predictions are obtained for the effective Majorana mass Mee, the absolute mass scale and the Majorana-type CP violating phases.

scholarly journals ELECTROWEAKSU(4)L⊗U(1)YMODELS WITHOUT EXOTIC ELECTRIC CHARGES

2009 ◽  
Vol 24 (25n26) ◽  
pp. 4923-4938 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Mass Spectrum ◽  
Standard Model ◽  
Mass Scale ◽  
Boson Mass ◽  
Gauge Models ◽  
The Standard Model ◽  
The One

For the particular class of SU (4)L⊗ U (1)Yelectroweak models without exotic electric charges, some plausible phenomenological predictions — such as the boson mass spectrum and charges of all the fermions involved therein — are made by using the algebraical approach of the exactly solving method for gauge models with high symmetries. Along with the one-parameter resulting mass scale (to be confirmed at TeV scale in LHC) our approach predicts the exact expressions of the charges (both electric and neutral) in the fermion sector, while all the Standard Model phenomenology is naturally recovered.

scholarly journals Unitarily inequivalent vacua and long-range forces: Phenomenology with scalar boson mass-shift

2020 ◽  
Vol 35 (17) ◽  
pp. 2050139
Author(s):  
Quan Le Thien ◽  
Dennis E. Krause
Keyword(s):  
Long Range ◽  
Vacuum State ◽  
Mass Shift ◽  
Boson Mass ◽  
Exchange Potential ◽  
Beyond The Standard Model ◽  
Scalar Boson ◽  
Boson Exchange ◽  
The One ◽  
The Impact

We explore the impact of a sudden shift in the mass of a scalar boson field on long-range forces mediated by this field under the framework of unitarily inequivalent vacua. Since the search for new long-range forces is an active experimental area probing physics beyond the Standard Model, the consequence of a non-trivial vacuum state of a scalar boson on these experiments is elucidated. We show that while the mass shift affects the one-boson exchange potential, the Casimir force remains only dependent on the vacuum state.

scholarly journals Clues on the Majorana scale from scalar resonances at the LHC

2017 ◽  
Vol 32 (06) ◽  
pp. 1750035 ◽  
Author(s):  
Oliver Fischer
Keyword(s):  
Hadron Collider ◽  
Planck Scale ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
High Energy ◽  
Mass Scale ◽  
Particle Spectrum ◽  
Neutrino Sector ◽  
Decay Properties ◽  
The Hill

In order to address the observation of the neutrino oscillations and the metastability of the Standard Model (SM), we extend the fermion sector with two right-handed (i.e. sterile) neutrinos, and the scalar sector of the SM with a real scalar, the Hill field. The latter takes the role of a Majoron and generates the Majorana masses for the neutrino sector, such that the particle spectrum features two CP-even scalars h1 and h2, and also two heavy, mass degenerate neutrinos. When the h1 is identified with the scalar resonance at [Formula: see text] 125 GeV and the condition is imposed that the h1 self-coupling and its running vanish at the Planck scale, the scalar mixing and the vacuum expectation value of the Hill field are fixed by the h2 mass. The h2 can be searched for at the LHC, and it has prospects of being discovered for the target integrated luminosities of the HL-LHC and the Future Circular hadron Collider (FCC-hh) when its mass is on the weak scale. The knowledge of the h2 mass and its decay properties can yield an insight into its coupling to the heavy neutrinos, and thus also on the heavy neutrino mass scale. This yields an interesting connection between potentially detectable heavy scalars in high-energy proton collisions and the mass scale of the heavy neutrinos that is testable at the LHC and at future colliders.

scholarly journals DAMPE excess from decaying right-handed neutrino dark matter

2018 ◽  
Vol 33 (27) ◽  
pp. 1850157 ◽  
Author(s):  
Nobuchika Okada ◽  
Osamu Seto
Keyword(s):  
Dark Matter ◽  
Mass Formula ◽  
Hadron Collider ◽  
Planck Scale ◽  
Gauge Coupling ◽  
Dark Matter Particle ◽  
Cosmic Ray ◽  
High Energy ◽  
Boson Mass ◽  
Late Time

The flux of high-energy cosmic-ray electrons plus positrons recently measured by the DArk Matter Particle Explorer (DAMPE) exhibits a tentative peak excess at an energy of around 1.4 TeV. In this paper, we consider the minimal gauged U(1)[Formula: see text] model with a right-handed neutrino (RHN) dark matter (DM) and interpret the DAMPE peak with a late-time decay of the RHN DM into [Formula: see text]. We find that a DM lifetime [Formula: see text] can fit the DAMPE peak with a DM mass [Formula: see text]. This favored lifetime is close to the current bound on it by Fermi-LAT, our decaying RHN DM can be tested, once the measurement of cosmic gamma ray flux is improved. The RHN DM communicates with the Standard Model particles through the U(1)[Formula: see text] gauge boson ([Formula: see text] boson), and its thermal relic abundance is controlled by only three free parameters: [Formula: see text], the U(1)[Formula: see text] gauge coupling [Formula: see text], and the [Formula: see text] boson mass [Formula: see text]. For [Formula: see text], the rest of the parameters are restricted to be [Formula: see text] and [Formula: see text], in order to reproduce the observed DM relic density and to avoid the Landau pole for running [Formula: see text] below the Planck scale. This allowed region will be tested by the search for a [Formula: see text] boson resonance at the future Large Hadron Collider.

scholarly journals Neutrino masses, vacuum stability and quantum gravity prediction for the mass of the top quark

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Guillem Domènech ◽  
Mark Goodsell ◽  
Christof Wetterich
Keyword(s):  
Quantum Gravity ◽  
Top Quark ◽  
Quark Mass ◽  
Scalar Potential ◽  
Planck Scale ◽  
Neutrino Masses ◽  
Top Quark Mass ◽  
Vacuum Stability ◽  
Intermediate Scale ◽  
Yukawa Couplings

Abstract A general prediction from asymptotically safe quantum gravity is the approximate vanishing of all quartic scalar couplings at the UV fixed point beyond the Planck scale. A vanishing Higgs doublet quartic coupling near the Planck scale translates into a prediction for the ratio between the mass of the Higgs boson MH and the top quark Mt. If only the standard model particles contribute to the running of couplings below the Planck mass, the observed MH∼ 125 GeV results in the prediction for the top quark mass Mt∼ 171 GeV, in agreement with recent measurements. In this work, we study how the asymptotic safety prediction for the top quark mass is affected by possible physics at an intermediate scale. We investigate the effect of an SU(2) triplet scalar and right-handed neutrinos, needed to explain the tiny mass of left-handed neutrinos. For pure seesaw II, with no or very heavy right handed neutrinos, the top mass can increase to Mt ∼ 172.5 GeV for a triplet mass of M∆ ∼ 108GeV. Right handed neutrino masses at an intermediate scale increase the uncertainty of the predictions of Mt due to unknown Yukawa couplings of the right-handed neutrinos and a cubic interaction in the scalar potential. For an appropriate range of Yukawa couplings there is no longer an issue of vacuum stability.

scholarly journals Electroweak symmetry breaking in the inverse seesaw mechanism

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Sanjoy Mandal ◽  
Rahul Srivastava ◽  
José W. F. Valle
Keyword(s):  
Planck Scale ◽  
Lepton Number ◽  
Electroweak Symmetry Breaking ◽  
Electroweak Symmetry ◽  
Seesaw Mechanism ◽  
Yukawa Couplings ◽  
Lepton Number Violation ◽  
Higgs Vacuum ◽  
The Standard Model ◽  
The Stability

Abstract We investigate the stability of Higgs potential in inverse seesaw models. We derive the full two-loop RGEs of the relevant parameters, such as the quartic Higgs self-coupling, taking thresholds into account. We find that for relatively large Yukawa couplings the Higgs quartic self-coupling goes negative well below the Standard Model instability scale ∼ 1010 GeV. We show, however, that the “dynamical” inverse seesaw with spontaneous lepton number violation can lead to a completely consistent and stable Higgs vacuum up to the Planck scale.

scholarly journals BOSON MASS SPECTRUM INSU(4)L⊗U(1)YMODEL WITH EXOTIC ELECTRIC CHARGES

2009 ◽  
Vol 24 (22) ◽  
pp. 1731-1742 ◽  
Author(s):  
ADRIAN PALCU
Keyword(s):  
Mass Spectrum ◽  
Mass Scale ◽  
Boson Mass ◽  
Gauge Models

The boson mass spectrum of the electroweak SU (4)L⊗ U (1)Ymodel with exotic electric charges is investigated by using the algebraical approach supplied by the method of solving gauge models with high symmetries. Our approach predicts for the boson sector a one-parameter mass scale to be tuned in order to match the data obtained at LHC, LEP, CDF.

scholarly journals Pathways to relativistic curved momentum spaces: de Sitter case study

2016 ◽  
Vol 25 (02) ◽  
pp. 1650027 ◽  
Author(s):  
Giovanni Amelino-Camelia ◽  
Giulia Gubitosi ◽  
Giovanni Palmisano
Keyword(s):  
Momentum Space ◽  
Hopf Algebras ◽  
Affine Connection ◽  
Planck Scale ◽  
Test Case ◽  
De Sitter ◽  
Group Manifold ◽  
The One ◽  
Natural Test

Several arguments suggest that the Planck scale could be the characteristic scale of curvature of momentum space. As other recent studies, we assume that the metric of momentum space determines the condition of on-shellness while the momentum space affine connection governs the form of the law of composition of momenta. We show that the possible choices of laws of composition of momenta are more numerous than the possible choices of affine connection on a momentum space. This motivates us to propose a new prescription for associating an affine connection to momentum composition, which we compare to the one most used in the recent literature. We find that the two prescriptions lead to the same picture of the so-called [Formula: see text]-momentum space, with de Sitter (dS) metric and [Formula: see text]-Poincaré connection. We then show that in the case of “proper dS momentum space”, with the dS metric and its Levi–Civita connection, the two prescriptions are inequivalent. Our novel prescription leads to a picture of proper dS momentum space which is DSR-relativistic and is characterized by a commutative law of composition of momenta, a possibility for which no explicit curved momentum space picture had been previously found. This momentum space can serve as laboratory for the exploration of the properties of DSR-relativistic theories which are not connected to group-manifold momentum spaces and Hopf algebras, and is a natural test case for the study of momentum spaces with commutative, and yet deformed, laws of composition of momenta.

scholarly journals Flavour effects in gravitational leptogenesis

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Rome Samanta ◽  
Satyabrata Datta
Keyword(s):  
Mass Spectrum ◽  
Chemical Potential ◽  
Mass Scale ◽  
Lepton Number ◽  
Type I ◽  
Lepton Asymmetry ◽  
Seesaw Mechanism ◽  
Set Up ◽  
The Right ◽  
Lepton Number Violating

Abstract Within the Type-I seesaw mechanism, quantum effects of the right-handed (RH) neutrinos in the gravitational background lead to an asymmetric propagation of lepton and anti-leptons which induces a Ricci scalar and neutrino Dirac-Yukawa coupling dependent chemical potential and therefore a lepton asymmetry in equilibrium. At high temperature, lepton number violating scattering processes try to maintain a dynamically generated lepton asymmetry in equilibrium. However, when the temperature drops down, the interactions become weaker, and the asymmetry freezes out. The frozen out asymmetry can act as a pre-existing asymmetry prior to the standard Fukugita-Yanagida leptogenesis phase (Ti ∼ Mi, where Mi is the mass of ith RH neutrino). It is then natural to consider the viability of gravitational leptogenesis for a given RH mass spectrum which is not consistent with successful leptogenesis from decays. Primary threat to this gravity-induced lepton asymmetry to be able to successfully reproduce the observed baryon-to-photon ratio is the lepton number violating washout processes at Ti ∼ Mi. In a minimal seesaw set up with two RH neutrinos, these washout processes are strong enough to erase a pre-existing asymmetry of significant magnitude. We show that when effects of flavour on the washout processes are taken into account, the mechanism opens up the possibility of successful leptogenesis (gravitational) for a mass spectrum M2 » 109GeV » M1 with M1 ≳ 6.3 × 106 GeV. We then briefly discuss how, in general, the mechanism leaves its imprints on the low energy CP phases and absolute light neutrino mass scale.

Sign in / Sign up

Export Citation Format

Share Document