15150619
Electric Dipole Moments in the MSSM Reloaded
We present a detailed study of the Thallium, neutron, Mercury and deuteron electric dipole moments (EDMs) in the CP-violating Minimal Supersymmetric extension of the Standard Model (MSSM). We take into account the complete set of one-loop graphs, the dominant Higgs-mediated two-loop diagrams, the complete CP-odd dimension-six Weinberg operator and the Higgs-mediated four-fermion operators. We improve upon earlier calculations by including the resummation effects due to CP-violating Higgs-boson mixing and to threshold corrections to the Yukawa couplings of all up- and down-type quarks and charged leptons. As an application of our study, we analyse the EDM constraints on the CPX, trimixing and Maximally CP- and Minimally Flavour-Violating (MCPMFV) scenarios. Cancellations may occur among the CP-violating contributions to the three measured EDMs arising from the 6 CP-violating phases in the MCPMFV scenario, leaving open the possibility of relatively large contributions to other CP-violating observables. The analytic expressions for the EDMs are implemented in an updated version of the code CPsuperH2.0.
3289948
Flavour geometry and effective Yukawa couplings in the MSSM
We present a new geometric approach to the flavour decomposition of an arbitrary soft supersymmetry-breaking sector in the MSSM. Our approach is based on the geometry that results from the quark and lepton Yukawa couplings, and enables us to derive the necessary and sufficient conditions for a linearly-independent basis of matrices related to the completeness of the internal [SU(3)⊗U(1)]5 flavour space. In a second step, we calculate the effective Yukawa couplings that are enhanced at large values of tan β for general soft supersymmetry-breaking mass parameters. We highlight the contributions due to non-universal terms in the flavour decompositions of the sfermion mass matrices. We present numerical examples illustrating how such terms are induced by renormalization-group evolution starting from universal input boundary conditions, and demonstrate their importance for the flavour-violating effective Yukawa couplings of quarks.
43894133
A geometric approach to CP violation: applications to the MCPMFV SUSY model
We analyze the constraints imposed by experimental upper limits on electric dipole moments (EDMs) within the Maximally CP -and Minimally Flavour-Violating (MCPMFV) version of the MSSM. Since the MCPMFV scenario has 6 non-standard CP -violating phases, in addition to the CP -odd QCD vacuum phase θQCD, cancellations may occur among the CP -violating contributions to the three measured EDMs, those of 205Tl, the neutron and 199Hg, leaving open the possibility of relatively large values of the other CP -violating observables. We develop a novel geometric method that uses the small-phase approximation as a starting point, takes the existing EDM constraints into account, and enables us to find maximal values of other CP -violating observables, such as the EDMs of the Deuteron and muon, the CP -violating asymmetry in b→sγ decay, and the B s mixing phase. We apply this geometric method to provide upper limits on these observables within specific benchmark supersymmetric scenarios, including extensions that allow for a non-zero θQCD.
121878109
Proton decay with a light gravitino or axino
We consider proton decay in supersymmetric models with a gravitino or axino lighter than the proton. This consideration leads to a stringent limit on the R-parity and B-violating Yukawa coupling of the superpotential operator U{sub i}{sup c}D{sub j}{sup c}D{sub k}{sup c} as {lambda}{sub 112}{sup {double_prime}}{le}10{sup {minus}15}(m{sub 3/2}/eV) for a light gravitino, and {lambda}{sub 112}{sup {double_prime}}{le}10{sup {minus}15}(F{sub a}/10{sup 10} GeV) for a light Dine-Fischler-Srednicki-Zhitnitskii axino. For the hadronic axino, the constraint is weakened by a factor of 10{sup 3}. {copyright} {ital 1997} {ital The American Physical Society}
1562637
Remarks on the upper bounds on the Higgs boson mass from triviality.
We study the effects of the one-loop matching conditions on Higgs boson and top quark masses on the triviality bounds on the Higgs boson mass using {beta}{sub {lambda}} with corrected two-loop coefficients. We obtain quite higher results than previous ones and observe that the triviality bounds are not nearly influenced by varying the top quark mass over the range measured at CDF and D0. The effects of typographical errors in {beta}{sub {lambda}}{sup (2)} and the one-loop matching condition on the top quark mass are negligible. We estimate the size of the effects on the triviality bounds from the one-loop matching condition on the Higgs boson mass. {copyright} {ital 1996 The American Physical Society.}
119107944
Singlino-driven electroweak baryogenesis in the next-to-MSSM
Abstract We explore a new possibility of electroweak baryogenesis in the next-to-minimal supersymmetric standard model. In this model, a strong first-order electroweak phase transition can be achieved due to the additional singlet Higgs field. The new impact of its superpartner (singlino) on the baryon asymmetry is investigated by employing the closed-time-path formalism. We find that the CP violating source term fueled by the singlino could be large enough to generate the observed baryon asymmetry of the Universe without any conflicts with the current constraints from the non-observation of the thallium, neutron and mercury electric dipole moments.
14152006
The sdB+M Eclipsing System HW Virginis and its Circumbinary Planets
For the very short period subdwarf B eclipsing binary HW Vir, we present new CCD photometry made from 2000 through 2008. In order to obtain consistency of the binary parameters, our new light curves, showing sharp eclipses and a striking reflection effect, were analyzed simultaneously with previously published radial velocity data. The secondary star parameters of M 2 = 0.14 M ?, R 2 = 0.18 R ?, and T 2 = 3084 K are consistent with those of an M6-7 main-sequence star. A credibility issue regarding bolometric corrections is emphasized. More than 250 times of minimum light, including our 41 timings and spanning more than 24 yr, were used for a period study. From a detailed analysis of the O ? C diagram, it emerged that the orbital period of HW Vir has varied as a combination of a downward-opening parabola and two sinusoidal variations, with cycle lengths of P 3 = 15.8 yr and P 4 = 9.1 yr and semiamplitudes of K 3 = 77 s and K 4 = 23 s, respectively. The continuous period decrease with a rate of ?8.28 ? 10?9 days yr?1 may be produced by angular momentum loss due to magnetic stellar wind braking but not by gravitational radiation. Of the possible causes of the cyclical components of the period change, apsidal motion and magnetic period modulation can be ruled out. The most reasonable explanation of both cyclical variations is a pair of light-travel-time effects driven by the presence of two substellar companions with projected masses of M 3sin i 3 = 19.2 M Jup and M 4sin i 4 = 8.5 M Jup. The two objects are the first circumbinary planets known to have been formed in a protoplanetary disk as well the first ones discovered by using the eclipse-timing method. The detection implies that planets could be common around binary stars just as are planets around single stars and demonstrates that planetary systems formed in a circumbinary disk can survive over long timescales. Depending on the thermal inertia of their massive atmospheres, the hemispheres of the planets turned toward the stars can experience substantial reciprocating temperature changes during the minutes-long primary eclipse intervals.
119232273
THE FIRST COMPREHENSIVE PHOTOMETRIC STUDY OF THE ALGOL-TYPE SYSTEM CL AURIGAE
We present the first extensive photometric results of CL Aur from our BVRI CCD photometry made on 22 nights from 2003 November to 2005 February. Fifteen new timings of minimum light were obtained. During the past 104 yr, the orbital period has varied due to a periodic oscillation superposed on a continuous period increase. The period and semi-amplitude of the oscillation are about 21.6 yr and 0.0133 day, respectively. This detail is interpreted as a light-travel-time effect due to a low-luminosity K-type star gravitationally bound to the CL Aur close system. Our photometric study indicates that CL Aur is a relatively short-period Algol-type binary with values of q = 0.602 and i = 882. Mass transfer from the secondary to the primary eclipsing component is at least partly responsible for the observed secular period change with a rate of dP/dt = +1.4 × 10–7 days yr–1. A cool spot model has been calculated but we think that an alternative hot-spot model resulting from a gas stream impact on the hot star is more reasonable despite two difficulties with the explanation. Absolute dimensions of the eclipsing system are deduced and its present state is compared with tracks for single star and conservative close binary evolution. Finally, we examine the possible reconciliation of two different calculations of the luminosity of the hot spot and a re-interpretation of the secular term of the period variability.
25175
New precision limit on the strange vector form factors of the proton.
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624  GeV2 and beam energy E(b) = 3.48  GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors.
119056575
mu- tau Symmetry and Radiatively Generated Leptogenesis
We consider a $\ensuremath{\mu}\ensuremath{-}\ensuremath{\tau}$ symmetry in neutrino sectors realized at the GUT scale in the context of a seesaw model. In our scenario, the exact $\ensuremath{\mu}\ensuremath{-}\ensuremath{\tau}$ symmetry realized in the basis where the charged lepton and heavy Majorana neutrino mass matrices are diagonal leads to vanishing lepton asymmetries. We find that, in the minimal supersymmetric extension of the seesaw model with large $\mathrm{tan}﻿\ensuremath{\beta}$, the renormalization group (RG) evolution from the GUT scale to seesaw scale can induce a successful leptogenesis even without introducing any symmetry breaking terms by hand, whereas such RG effects lead to tiny deviations of ${\ensuremath{\theta}}_{23}$ and ${\ensuremath{\theta}}_{13}$ from $\ensuremath{\pi}/4$ and zero, respectively. It is shown that the right amount of the baryon asymmetry ${\ensuremath{\eta}}_{B}$ can be achieved via so-called resonant leptogenesis, which can be realized at rather low seesaw scale with large $\mathrm{tan}﻿\ensuremath{\beta}$ in our scenario so that the well-known gravitino problem is safely avoided.
867013
Quark-Lepton Complementarity with Renormalization Effects through Threshold Corrections
The recent experimental measurements of the solar neutrino mixing angle θ sol and the Cabibbo mixing angle θ C reveal a surprising relation, θ sol+ θ C ’ π 4 . While this empirical relation has been interpreted as a support of the idea of grand unification, it may be merely accidental in the sense that reproducing the relation at a low energy in the framework of grand unification may depend strongly on the renormalization effects whose size can vary with the choice of parameter space. We note that the lepton mixing matrix derived from quark-lepton unification can lead to a shift of the complementarity relation at low energy. While the renormalization group effects generally lead to additive contribution on top of the shift, we show that the threshold corrections which may exist in some intermediate scale new physics such as supersymmetric standard model can diminish it, so we can achieve the complementarity relation at a low energy.