14040414
Anomalies, Fayet-Iliopoulos terms, and the consistency of orbifold field theories
We study the consistency of orbifold field theories and clarify to what extent the condition of having an anomaly-free spectrum of zero-modes is sufficient t o guarantee it. Preservation of gauge invariance at the quantum level is possible, although at the price, in general, of introducing operators that break the 5d local parity. These operators are, however, perfectly consistent with the orbifold projection. We also clarify the relation between localized Fayet–Iliopoulos (FI) terms and anomalies. These terms can be consistently added, breaking neither local supersymmetry nor gauge symmetry. In the framework of supergravity the localized FI term arises as the boundary completion of a bulk interaction term: given the bulk Lagrangian the FI is fixed by gauge invariance.
122546935
Supersymmetry, R-parity breaking and the neutrino magnetic moment
Abstract We show that supersymmetric theories with R -parity breaking naturally give rise to significant neutrino magnetic moments. In the minimal supersymmetric standard model the transition magnetic moment μ ν e ν μ can be as large as 10 −13 μ B ( μ B is the Bohr magneton). By requiring an SU (2) H horizontal symmetry of the lagrangian in the Yukawa-less limit, μ ν e ν μ may be one order magnitude larger. In this case the main naturalness constraint on the maximum μ ν e ν μ attainable is the electron mass value rather than the bound on the neutrino mass itself.
118630400
Minimal Flavour Violation with hierarchical squark masses
In a supersymmetric model with hierarchical squark masses we analyze a pattern of flavour symmetry breaking centered on the special role of the top Yukawa coupling and, by extension, of the full Yukawa couplings for the up-type quarks. For sufficiently heavy squarks of the first and second generation this leads to effective Minimal Flavour Violation of the Flavour Changing Neutral Current amplitudes. For this to happen we determine the bounds on the masses of the heavy squarks with QCD corrections taken into account, properly including previously neglected effects. We believe that the view presented in this paper altogether strengthens the case for hierarchical sfermions.
118381299
Composite vectors at the Large Hadron Collider
An unspecified strong dynamics may give rise to composite vectors sufficiently light that their interactions, among themselves or with the electroweak gauge bosons, be approximately described by an effective Lagrangian invariant under SU(2)L × SU(2)R/SU(2)L+R. We study the production at the LHC of two such states by vector boson fusion or by the Drell-Yan process in this general framework and we compare it with the case of gauge vectors from a SU(2)L × SU(2)R × SU(2)N gauge model spontaneously broken to the diagonal SU(2) subgroup by a generic σ-model. Special attention is payed to the asymptotic behaviour of the different amplitudes in both cases. The expected rates of multi-lepton events from the decay of the composite vectors are also given. A thorough phenomenological analysis and the evaluation of the backgrounds to such signals, aiming at assessing the visibility of composite-vector pairs at the LHC, is instead deferred to future work.
27801366
Grand unification and the supersymmetric threshold.
It is shown that grand unification of the minimal supersymmetric standard model does not lead to a prediction for the scale of the superpartner masses, even if the inputs {alpha}, sin{sup 2}{theta}, and {alpha}{sub {ital s}} are known exactly.
11346163
What is the limit on the Higgs mass
Abstract We obtain the bounds on all the gauge invariant, flavour symmetric, CP-even operators of dimension 6 that can affect the electroweak precision tests. For the preferred Higgs mass of about 100 GeV , their minimal scales range from 2 to 10 TeV. Depending on the individual operator, these limits are often significantly stronger than those quoted in the literature, when they exist at all. The impact, if any, of these bounds on the upper limit con the Higgs mass itself is discussed.
208865876
Measurements of jet multiplicity and differential production cross sections of Z + jets events in proton-proton collisions at √s = 7 TeV
Measurements of differential cross sections are presented for the production of a Z boson and at least one hadronic jet in proton-proton collisions at √s=7  TeV, recorded by the CMS detector, using a data sample corresponding to an integrated luminosity of 4.9  fb^(−1). The jet multiplicity distribution is measured for up to six jets. The differential cross sections are measured as a function of jet transverse momentum and pseudorapidity for the four highest transverse momentum jets. The distribution of the scalar sum of jet transverse momenta is also measured as a function of the jet multiplicity. The measurements are compared with theoretical predictions at leading and next-to-leading order in perturbative QCD.
218730825
Measurement of pseudorapidity distributions of charged particles in proton–proton collisions at √s = 8 TeV by the CMS and TOTEM experiments