Pure Gravity Mediation and Spontaneous B-L Breaking from Strong Dynamics

In pure gravity mediation (PGM), the most minimal scheme for the mediation of supersymmetry (SUSY) breaking to the visible sector, soft masses for the standard model gauginos are generated at one loop rather than via direct couplings to the SUSY-breaking field. In any concrete implementation of PGM, the SUSY-breaking field is therefore required to carry nonzero charge under some global or local symmetry. As we point out in this note, a prime candidate for such a symmetry might be B-L, the Abelian gauge symmetry associated with the difference between baryon number B and lepton number L. The F-term of the SUSY-breaking field then not only breaks SUSY, but also B-L, which relates the respective spontaneous breaking of SUSY and B-L at a fundamental level. As a particularly interesting consequence, we find that the heavy Majorana neutrino mass scale ends up being tied to the gravitino mass, Lambda_N ~ m_3/2. Assuming nonthermal leptogenesis to be responsible for the generation of the baryon asymmetry of the universe, this connection may then explain why SUSY necessarily needs to be broken at a rather high energy scale, so that m_3/2 >~ 1000 TeV in accord with the concept of PGM. We illustrate our idea by means of a minimal model of dynamical SUSY breaking, in which B-L is identified as a weakly gauged flavor symmetry. We also discuss the effect of the B-L gauge dynamics on the superparticle mass spectrum as well as the resulting constraints on the parameter space of our model. In particular, we comment on the role of the B-L D-term.Comment: 25 pages, 1 figur

Quark and lepton masses and mixing in SO(10) with a GUT-scale vector matter

We explore in detail the effective matter fermion mass sum-rules in a class of renormalizable SUSY SO(10) grand unified models where the quark and lepton mass and mixing patterns originate from non-decoupling effects of an extra vector matter multiplet living around the unification scale. If the renormalizable type-II contribution governed by the SU(2)_L-triplet in 54_H dominates the seesaw formula, we obtain an interesting correlation between the maximality of the atmospheric neutrino mixing and the proximity of y_s/y_b to V_cb in the quark sector.Comment: 13 pages, 1 figure, 2 tables; v2: major update, references adde

nuMSM--Predictions for Neutrinoless Double Beta Decay

We give the prediction on the effective Majorana mass for neutrinoless double $\beta$ decay in a simple extension of the Standard Model (nuMSM). The model adds three right-handed neutrinos with masses smaller than the electroweak scale, and explains dark matter of the Universe. This leads to constraints 1.3meV<m_{bb}^{NH}<3.4meV in normal neutrino mass hierarchy and 13meV<m_{bb}^{IH}<50meV in inverted hierarchy.Comment: 5 page

Minimal Seesaw as an Ultraviolet Insensitive Cure for the Problems of Anomaly Mediation

We show that an intermediate scale supersymmetric left-right seesaw scenario with automatic R-parity conservation can cure the problem of tachyonic slepton masses that arises when supersymmetry is broken by anomaly mediation, while preserving ultraviolet insensitivity. The reason for this is the existence of light B - L = 2 higgses with yukawa couplings to the charged leptons. We find these theories to have distinct predictions compared to the usual mSUGRA and gauge mediated models as well as the minimal AMSB models. Such predictions include a condensed gaugino mass spectrum and possibly a correspondingly condensed sfermion spectrum.Comment: 19 pages, 1 figur

Observing Signals of the Bulk Matter RS Model through Rare Decays of SUSY Particles

The bulk matter Randall-Sundrum (RS) model is a setup where Standard Model (SM) matter and gauge fields reside in the bulk of 5D warped spacetime while the Higgs field is confined on the IR brane. The wavefunctions of the 1st and 2nd generation matter particles are localized towards the UV brane and those of the 3rd generation towards the IR brane, so that the hierarchical structure of the Yukawa couplings arises geometrically without hierarchy in fundamental parameters. This paper discusses an experimental test of this model in the case where the Kaluza-Klein scale is far above the collider scale, but the model is combined with 5D Minimal SUSY Standard Model (MSSM) and SUSY particles are in the reach of collider experiments. A general SUSY breaking mass spectrum consistent with the bulk matter RS model is considered: SUSY breaking sector locates on the IR brane and its effects are mediated to 5D MSSM through a hybrid of gravity mediation, gaugino mediation and gauge mediation. This paper argues that it is possible to observe the signals of the bulk matter RS model through rare decays of "almost SU(2) singlet mass eigenstates" that are induced by flavor-violating gravity mediation contributions to matter soft SUSY breaking terms

Contribution of Type Ia and Type II Supernovae for Intra-Cluster Medium Enrichment

The origin of the chemical composition of the intracluster medium (ICM) is discussed in this paper. In particular, the contribution from Type Ia supernovae (SNe Ia) to the ICM enrichment is shown to exist by adopting the fitting formulas which have been used in the analysis of the solar system abundances. Our analysis means that we can use the frequency of SNe Ia relative to SNe II as the better measure than $M_{Fe, SN Ia}/M_{Fe, total}$ for estimating the contribution of SNe Ia. Moreover, the chemical compositions of ICMs are shown to be similar to that of the solar system abundances. We can also reproduce the sulfur/iron abundance ratio within a factor of 2, which means that the abundance problem of sulfur needs not to be emphasized too strongly. We need more precise observations to conclude whether ICMs really suffer the shortage problem of sulfur or not.Comment: 20 pages, LaTeX text and 15 postscript figures. Accepted for publication in Astrophysical Journa

A Model for Neutrino and Charged Lepton Masses in Extra Dimensions

We propose a model with one large submm size extra dimension in which the gravity and right-handed (RH) neutrino propagate, but the three Standard Model (SM) families are confined to fat branes of TeV^(-1) size or smaller. The charged leptons and the light neutrinos receive mass from the five dimensional Yukawa couplings with the SM singlet neutrino via electroweak Higgs, while the KK excitations of the SM singlet neutrino gets large TeV scale masses from the five dimensional Yukawa coupling with an electroweak singlet Higgs. The model gives non-hierarchical light neutrino masses, accommodate hierarchical charged lepton masses, and naturally explain why the light neutrino masses are so much smaller compared to the charged lepton masses. Large neutrino mixing is naturally expected in this scenario. The light neutrinos are Dirac particles in this model, hence neutrinoless double beta decay is not allowed. The model has also several interesting collider implications and can be tested at the LHC.Comment: 11 pages, no figure

Minimally Allowed Neutrinoless Double Beta Decay Rates From Approximate Flavor Symmetries

Neutrinoless double beta decay ($\beta\beta0\nu$) is among the only realistic probes of Majorana neutrinos. In the standard scenario, dominated by light neutrino exchange, the process amplitude is proportional to $m_{ee}$, the $e-e$ element of the Majorana mass matrix. Naively, current data allows for vanishing $m_{ee}$, but this should be protected by an appropriate flavor symmetry. All such symmetries lead to mass matrices inconsistent with oscillation phenomenology. I perform a spurion analysis to break all possible Abelian symmetries that guarantee vanishing $\beta\beta0\nu$ rates and search for minimally allowed values. I survey 230 broken structures to yield $m_{ee}$ values and current phenomenological constraints under a variety of scenarios. This analysis also extracts predictions for both neutrino oscillation parameters and kinematic quantities. Assuming reasonable tuning levels, I find that $m_{ee}>4\times 10^{-6}$ eV at 99% confidence. Bounds below this value might indicate the Dirac neutrino nature or the existence of new light (eV-MeV scale) degrees of freedom that can potentially be probed elsewhere.Comment: 19 Pages, 4 .eps Figures, 3 Table