Eviction of a 125 GeV "heavy"-Higgs from the MSSM

We prove that the present experimental constraints are already enough to rule out the possibility of the ~125 GeV Higgs found at LHC being the second lightest Higgs in a general MSSM context, even with explicit CP violation in the Higgs potential. Contrary to previous studies, we are able to eliminate this possibility analytically, using simple expressions for a relatively small number of observables. We show that the present LHC constraints on the diphoton signal strength, tau-tau production through Higgs and BR(B -> X_s gamma) are enough to preclude the possibility of H_2 being the observed Higgs with m_H~125 GeV within an MSSM context, without leaving room for finely tuned cancellations. As a by-product, we also comment on the difficulties of an MSSM interpretation of the excess in the gamma-gamma production cross section recently found at CMS that could correspond to a second Higgs resonance at m_H~136 GeV.Comment: 38 pages, 9 figures. Final version accepted at JHEP. Sections 2, 3 and appendices simplified. Experimental results updated, several references added. Small typos corrected and a new comparison of approximate formulas with full expressions include

Cross-ownership, R&D Spillovers, and Antitrust Policy

This paper considers cost-reducing R&D investment with spillovers in a Cournot oligopoly with minority shareholdings. We find that, with high market concentration and sufficiently convex demand, there is no scope for cross-ownership to improve welfare regardless of spillover levels. Otherwise, there is scope for cross-ownership provided that spillovers are sufficiently large. The socially optimal degree of cross-ownership increases with the number of firms, with the elasticity of demand and of the innovation function, and with the extent of spillover effects. In terms of consumer surplus standard, the scope for cross-ownership is greatly reduced even under low market concentration

Controlled flavor violation in the MSSM from a unified Δ(27)\Delta(27) flavor symmetry

We study the phenomenology of a unified supersymmetric theory with a flavor symmetry $\Delta(27)$. The model accommodates quark and lepton masses, mixing angles and CP phases. In this model, the Dirac and Majorana mass matrices have a unified texture zero structure in the $(1,1)$ entry that leads to the Gatto-Sartori-Tonin relation between the Cabibbo angle and ratios of the masses in the quark sectors, and to a natural departure from zero of the $\theta_{13}^\ell$ angle in the lepton sector. We derive the flavor structures of the trilinears and soft mass matrices, and show their general non-universality. This causes large flavor violating effects. As a consequence, the parameter space for this model is constrained, allowing it to be (dis)proven by flavor violation searches in the next decade. Although the results are model specific, we compare them to previous studies to show similar flavour effects (and associated constraints) are expected in general in supersymmetric flavor models, and may be used to distinguish them.Comment: 21 pages, 6 figure

Leptogenesis in Δ(27)\Delta(27) with a Universal Texture Zero

We investigate the possibility of viable leptogenesis in an appealing $\Delta(27)$ model with a universal texture zero in the (1,1) entry. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both $N_1$ and $N_2$ right-handed neutrino decays. The $N_1$-dominated scenario is successful and the most natural option for the model, with $M_1 \in [10^9, 10^{12}]$ GeV, and $M_1/M_2 \in [0.002, 0.1]$, which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the $N_2$-dominated scenario, with the asymmetry in the electron flavour protected from $N_1$ washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy $M_1/M_2 < 0.002$, and $M_2$ relatively close to $M_3$, which is not a natural expectation of the $\Delta(27)$ model.Comment: v2: 20 pages, 2 figures. Version accepted in JHE

Muon and electron g−2g-2 and lepton masses in flavor models

The stringent experimental bound on $\mu \rightarrow e \gamma$ is compatible with a simultaneous and sizable new physics contribution to the electron and muon anomalous magnetic moments $(g-2)_\ell$ ($\ell=e,\,\mu$), only if we assume a non-trivial flavor structure of the dipole operator coefficients. We propose a mechanism in which the realization of the $(g-2)_\ell$ correction is manifestly related to the mass generation through a flavor symmetry. A radiative flavon correction to the fermion mass gives a contribution to the anomalous magnetic moment. In this framework, we introduce a chiral enhancement from a non-trivial $\mathcal{O}(1)$ quartic coupling of the scalar potential. We show that the muon and electron anomalies can be simultaneously explained in a vast region of the parameter space with predicted vector-like mediators of masses as large as $M_\chi\in [0.6,2.5]$~TeV.Comment: 18 pages, 3 figures, 2 table

Implications of the Muon g-2 result on the flavour structure of the lepton mass matrix

The confirmation of the discrepancy with the Standard Model predictions in the anomalous magnetic moment by the Muon g-2 experiment at Fermilab points to a low scale of new physics. Flavour symmetries broken at low energies can account for this discrepancy but these models are much more restricted, as they would also generate off-diagonal entries in the dipole moment matrix. Therefore, if we assume that the observed discrepancy in the muon $g-2$ is explained by the contributions of a low-energy flavor symmetry, lepton flavour violating processes can constrain the structure of the lepton mass matrices and therefore the flavour symmetries themselves predicting these structures. We apply these ideas to several discrete flavour symmetries popular in the leptonic sector, such as $\Delta (27)$, $A_4$, and $A_5 \ltimes {\rm CP}$.Comment: 21 pages; v3: comments added, typos corrected, version accepted for publication in EPJ

Anomaly-free ALP from non-Abelian flavor symmetry

Motivated by the Xenon1T excess in electron-recoil measurements, we investigate the prospects of probing axion-like particles (ALP) in lepton flavor violation experiments. In particular, we identify such ALP as a pseudo-Goldstone from the spontaneous breaking of the flavor symmetries that explain the mixing structure of the Standard Model leptons. We present the case of the flavor symmetries being a non-Abelian U(2) and the ALP originating from its U(1) subgroup, which is anomaly-free with the Standard Model group. We build two explicit realistic examples that reproduce leptonic masses and mixings and show that the ALP which is consistent with Xenon1T anomaly could be probed by the proposed LFV experiments.Comment: 18 pages, 1 figur

Flavon vacuum alignment beyond SUSY

In flavor models the vacuum alignment of flavons is typically achieved via the $F$-terms of certain fields in the supersymmetric limit. We propose a method for preserving such alignments, up to a rescaling of the vacuum expectation values, even after supersymmetry (and the flavor symmetry) are softly broken, facilitating the vacuum alignment in models which are non-supersymmetric at low energies. Examples of models with different flavor groups, namely $A_4$, $T_7$, $S_4$ and $\Delta(27)$, are discussed.Comment: 28 pages + reference

LFV and g-2 in non-universal SUSY models with light higgsinos

We consider a supersymmetric type-I seesaw framework with non-universal scalar masses at the GUT scale to explain the long-standing discrepancy of the anomalous magnetic moment of the muon. We find that it is difficult to accommodate the muon g-2 while keeping charged-lepton flavor violating processes under control for the conventional SO(10)-based relation between the up sector and neutrino sector. However, such tension can be relaxed by adding a Georgi-Jarlskog factor for the Yukawa matrices, which requires a non-trivial GUT-based model. In this model, we find that both observables are compatible for small mixings, CKM-like, in the neutrino Dirac Yukawa matrix.Comment: 27 pages, 9 figure