Supersymmetry breaking in a warped slice with Majorana-type masses

We study the five-dimensional (5D) supergravity compactified on an orbifold S^1/Z_2, where the U(1)_R symmetry is gauged by the graviphoton with Z_2-even coupling. In contrast to the case of gauging with Z_2-odd coupling, this class of models has Majorana-type masses and allows the Scherk-Schwarz (SS) twist even in the warped spacetime. Starting from the off-shell formulation, we show that the supersymmetry is always broken in an orbifold slice of AdS_5, irrespective of the value of the SS twist parameter. We analyze the spectra of gaugino and gravitino in such background, and find the SS twist can provide sizable effects on them in the small warping region.Comment: 1+20 pages, 6 figure

Search for Lepton Flavour Violation in the Decay tau -> mu gamma

A search for the lepton flavour violating decay tau -> mu gamma has been performed using 221.4/fb of data collected at an e+e- centre-of-mass energy of 10.58 GeV with the BABAR detector at the PEP-II storage ring. The search has an efficiency of (7.45+/-0.65)% for an expected background level of 6.2+/-0.5 events. In the final sample 4 candidate events are selected. As there is no evidence for a signal in this data, for this preliminary result we set an upper limit of BR(tau -> mu gamma) < 9 x 10^-8 at 90%CL using the method of Feldman and Cousins.Comment: 7 pages, 3 encapsulated postscript figures, uses espcrc2.st

Probing quark compositeness at hadronic colliders : the case of polarized beams

A new handed interaction between subconstituents of quarks could be at the origin of some small parity violating effects in one-jet inclusive production. Within a few years, the Relativistic Heavy Ion Collider (RHIC) will be used as a polarized proton-proton collider. In this context, we analyse the possibilities of disentangling some new parity violating effects from the standard spin asymmetries which are expected due to the Standard Model QCD-Weak interference. We also explore the possibilities of placing some more stringent limits on the quark compositeness scale $\Lambda$ thanks to measurements of such spin asymmetries.Comment: 10 pages, Latex, 4 figures to be appende

Interpreting experimental bounds on D^0 - \bar{D^0} mixing in the presence of CP violation

We analyse the most recent experimental data regarding D^0 - \bar{D^0} mixing, allowing for CP violation. We focus on the dispersive part of the mixing amplitude, M^D_{12}, which is sensitive to new physics contributions. We obtain a constraint on the mixing amplitude: |M^D_{12}| < 6.2\times 10^{-11} MeV at 95% C.L. . This constraint is weaker by a factor of about three than the one which is obtained when no CP violation is assumed.Comment: 9 pages, revtex4; One reference updated, one reference added, footnote 3 correcte

Strange form factors of the proton: a new analysis of the neutrino (antineutrino) data of the BNL-734 experiment

We consider ratios of elastic neutrino(antineutrino)-proton cross sections measured by the Brookhaven BNL-734 experiment and use them to obtain the neutral current (NC) over charged current (CC) neutrino-antineutrino asymmetry. We discuss the sensitivity of these ratios and of the asymmetry to the electric, magnetic and axial strange form factors of the nucleon and to the axial cutoff mass M_A. We show that the effects of the nuclear structure and interactions on the asymmetry and, in general, on ratios of cross sections are negligible. We find some restrictions on the possible values of the parameters characterizing the strange form factors. We show that a precise measurement of the neutrino-antineutrino asymmetry would allow the extraction of the axial and vector magnetic strange form factors in a model independent way. The neutrino-antineutrino asymmetry turns out to be almost independent on the electric strange form factor and on the axial cutoff mass.Comment: 12 page

Spin asymmetries in one-jet production at RHIC with polarized proton beams : the effects of a hadrophilic Z'

We show that the measurement of some parity violating asymmetry in the production of a large ET jet could reveal the presence of a new hadrophilic Z' such as the one recently introduced to interpret possible departures from the Standard Model predictions both at LEP and at CDF. Such a measurement could be perform within a few years by the RHIC Spin Collaboration (RSC) using the Relativistic Heavy Ion Collider (RHIC) as a polarized proton-proton collider.Comment: 10 pages, latex file and 2 ps figure

Using untagged B^0 -> D K_S to determine gamma

It is shown that the weak phase gamma=arg(-V_{ud}V^*_{ub}V_{cb}V_{cd}^*) can be determined using only untagged decays B/Bbar--> D K_S. In order to reduce the uncertainty in gamma, we suggest combining information from B^{+-}--> DK^{+-} and from untagged B^0 decays, where the D meson is observed in common decay modes. Theoretical assumptions, which may further reduce the statistical error, are also discussed.Comment: 18 pages, same as published versio

Heavy Meson Description with a Screened Potential

We perform a quark model calculation of the $b\bar{b}$ and $c\bar{c}$ spectra from a screened funnel potential form suggested by unquenched lattice calculations. A connection between the lattice screening parameter and an effective gluon mass directly derived from QCD is established. Spin-spin energy splittings, leptonic widths and radiative decays are also examined providing a test for the description of the states.Comment: 17 pages, no figures, to appear in Phys. Rev.

FastJet user manual

FastJet is a C++ package that provides a broad range of jet finding and analysis tools. It includes efficient native implementations of all widely used 2-to-1 sequential recombination jet algorithms for pp and e+e- collisions, as well as access to 3rd party jet algorithms through a plugin mechanism, including all currently used cone algorithms. FastJet also provides means to facilitate the manipulation of jet substructure, including some common boosted heavy-object taggers, as well as tools for estimation of pileup and underlying-event noise levels, determination of jet areas and subtraction or suppression of noise in jets.Comment: 69 pages. FastJet 3 is available from http://fastjet.fr

Holographic approach to a minimal Higgsless model

In this work, following an holographic approach, we carry out a low energy effective study of a minimal Higgsless model based on SU(2) bulk symmetry broken by boundary conditions, both in flat and warped metric. The holographic procedure turns out to be an useful computation technique to achieve an effective four dimensional formulation of the model taking into account the corrections coming from the extra dimensional sector. This technique is used to compute both oblique and direct contributions to the electroweak parameters in presence of fermions delocalized along the fifth dimension.Comment: Latex file, 23 page