465148
SUPERGRAVITY RADIATIVE EFFECTS ON SOFT TERMS AND THE MU TERM
We compute quadratically divergent supergravity one-loop effects on soft supersymmetry-breaking parameters and the $\mu$ term in generic hidden sector supergravity models. These effects can significantly modify the matching condition for soft parameters at the Planck scale and also provide several new sources of the $\mu$ term which are naturally of order the weak scale. We also discuss some phenomenological implications of these effects, particularly the violation of the scalar mass universality which may lead to dangerous FCNC phenomena, and apply the results to superstring effective supergravity models.
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.
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.}
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}
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.
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.
118742346
Gaugino masses from gravitino at one loop
The N=1 supergravity coupled to chiral and Yang-Mills superfields is regarded as the ultraviolet theory of the supersymmetric Standard Model. The gravitino acquires a mass from the hidden sector and participate in mediating supersymmetry breaking to the visible sector. We consider the quantum effects of the gravitino and evaluate its contribution to the gaugino masses at one loop level, which turns out to be irrespective of the SM gauge couplings. Due to the universality of gravitino, its contribution to the gaugino masses can significantly modify the gaugino mass relations of other supersymmetry breaking mechanisms depending on the gravitino mass. For a given gaugino mass the gravitino mass cannot be arbitrarily large even when other supersymmetry breaking mechanisms are dominant.
56430796
Measurements of $D^{0}$ and $D^{*}$ Production in $p$ + $p$ Collisions at $\sqrt{s}$ = 200 GeV
We report measurements of charmed-hadron ($D^{0}$, $D^{*}$) production cross sections at mid-rapidity in $p$ + $p$ collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays $D^{0}\rightarrow K^{-}\pi^{+}$, $D^{*+}\rightarrow D^{0}\pi^{+}\rightarrow K^{-}\pi^{+}\pi^{+}$ and their charge conjugates, covering the $p_T$ range of 0.6$-$2.0 GeV/$c$ and 2.0$-$6.0 GeV/$c$ for $D^{0}$ and $D^{*+}$, respectively. From this analysis, the charm-pair production cross section at mid-rapidity is $d\sigma/dy|_{y=0}^{c\bar{c}}$ = 170 $\pm$ 45 (stat.) $^{+38}_{-59}$ (sys.) $\mu$b. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a Fixed-Order Next-to-Leading Logarithm calculation.
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.
15489354
Phenomenology of the radion in the Randall–Sundrum scenario at colliders
Abstract Phenomenology of a radion ( φ ) that stabilizes the modulus in the Randall–Sundrum scenario is considered. The radion couples to the trace of energy momentum tensor of the standard model (SM) with a strength suppressed only by a new scale ( Λ φ ) of an order of the electroweak scale. In particular, the effective coupling of a radion to two gluons is enhanced due to the trace anomaly of QCD. Therefore, its production cross section at hadron colliders could be enhanced, and the dominant decay mode of a relatively light radion is φ → gg , unlike the SM Higgs boson case. We also present constraints on the mass m φ and the new scale Λ φ from the Higgs search limit at LEP and perturbative unitarity bound.
26919092
A Measurement of the Michel Parameters in Leptonic Decays of the Tau
We have measured the spectral shape Michel parameters {rho} and {eta} using leptonic decays of the {tau}, recorded by the CLEO II detector. Assuming e-{mu} universality, we find {rho}{sub e{mu}}= 0.735 {+-} 0.013 {+-} 0.008 and {eta}{sub e{mu}} = 0.015 {+-} 0.061 {+-} 0.062, where the first error is statistical and the second systematic.