10475979
Primordial Fluctuations from Gaugino Condensation
I present a model for inflation based on the gaugino-dilaton dynamics of supersymmetry breaking. The inflaton is the dimension–1 scalar field φ related to the gaugino condensate via λT λ = φ. Recent work in this area is used to obtain two significant results: (1) Scalar density fluctuations at second horizon crossing are generated on scale λ with amplitude
121355086
Estimates for the probability of detecting neutral heavy leptons in hadron-initiated interactions
A consideration of two mechanisms for the production of neutral heavy leptons (${L}^{0}$'s) in hadron-initiated interactions lead to an estimate of ${10}^{\ensuremath{-}39}$ ${\mathrm{cm}}^{2}$ for the cross section per nucleon for observing the trimuons associated with the production of $\ensuremath{\mu}$-coupled ${L}^{0}$'s. This is well below the estimated background due to the production of a pair of ${\ensuremath{\rho}}^{0}$'s which decay into $\ensuremath{\mu}$ pairs.
13042203
Extensive air showers with TeV scale quantum gravity
One of the possible consequences of the existence of extra degrees of freedom beyond the electroweak scale is the increase of neutrino-nucleon cross sections ({sigma}{sub {nu}N}) beyond standard model predictions. At ultrahigh energies this may allow the existence of neutrino-initiated extensive air showers. In this paper, we examine the most relevant observables of such showers. Our analysis indicates that the future Pierre Auger Observatory could be potentially powerful in probing models with large compact dimensions.
119286304
Z'-gauge Bosons as Harbingers of Low Mass Strings
Massive Z'-gauge bosons act as excellent harbingers for string compactifications with a low string scale. In D-brane models they are associated to U(1) gauge symmetries that are either anomalous in four dimensions or exhibit a hidden higher dimensional anomaly. We discuss the possible signals of massive Z'-gauge bosons at hadron collider machines (Tevatron, LHC) in a minimal D-brane model consisting out of four stacks of D-branes. In this construction, there are two massive gauge bosons, which can be naturally associated with baryon number B and B-L (L being lepton number). Here baryon number is always anomalous in four dimensions, whereas the presence of a four-dimensional B-L anomaly depends on the U(1)-charges of the right handed neutrinos. In case B-L is anomaly free, a mass hierarchy between the two associated Z'-gauge bosons can be explained. In our phenomenological discussion about the possible discovery of massive Z'-gauge bosons, we take as a benchmark scenario the dijet plus W signal, recently observed by the CDF Collaboration at Tevatron. It reveals an excess in the dijet mass range 150 GeV/c^2, 4.1\sigma beyond SM expectations. We show that in the context of low-mass string theory this excess can be associated with the production and decay of a leptophobic Z', a singlet partner of SU(3) gluons coupled primarily to baryon number. Even if the CDF signal disappears, as indicated by the more recent D0 results, our analysis can still serve as the basis for future experimental search for massive Z'-gauge bosons in low string scale models. We provide the relevant cross sections for the production of Z'-gauge bosons in the TeV region, leading to predictions that are within reach of the present or the next LHC run.
119188244
LHC phenomenology of lowest massive Regge recurrences in the Randall-Sundrum orbifold
We consider string realizations of the Randall-Sundrum effective theory for electroweak symmetry breaking and explore the search for the lowest massive Regge excitation of the gluon and of the extra (color singlet) gauge boson inherent in D-brane constructions. In these curved backgrounds, the higher-spin Regge recurrences of standard model fields localized near the IR brane are warped down to close to the TeV range and hence can be produced at collider experiments. Assuming that the theory is weakly coupled, we make use of four gauge boson amplitudes evaluated near the first Regge pole to determine the discovery potential of LHC. We study the inclusive dijet mass spectrum in the central rapidity region |y{sub jet}| =}2.5 TeV. We find that with an integrated luminosity of 100 fb{sup -1}, the 5{sigma} discovery reach can be as high as 4.7 TeV. Observations of resonant structures in pp{yields}direct{gamma}+jet can provide interesting corroboration for string physics up to 3.0 TeV. We also study the ratio of dijet mass spectra at small and large scattering angles. We show that with the first fb{sup -1} such a ratio can probe lowest-lying Regge states for masses {approx}2.5 TeV.
120429995
PREDICTIONS FOR INCLUSIVE REACTIONS BASED ON A PARTON STRUCTURE OF HADRONS.
Abstract It is proposed that the asymptotic single-particle distributions f ( x )= x (d σ /d x ) in inclusive reactions should reflect the limiting longitudinal momentum distribution, ∼ νW 2 ( x ), of the hypothetical partons constituting a hadron. It is further argued that f ( x ) becomes, proportional to νW 2 ( x ) as x → 1. Predictions are then made for a large class of inclusive reactions based on our knowledge of νW 2 ( x ) from electroproduction data. For some of these (such as pp → π ± X), in which the predictions differ markedly from the Regge ones, present experiments distinctly favor ours.
56282466
Production of High Transverse Energy Events in p - Nucleus Collisions at 400-GeV/c
High-transverse-energy events produced in pp collisions at 400 GeV/c were studied using the large-acceptance Fermilab multiparticle spectrometer. The cross sections for such interactions exhibit an exponential dependence on transverse energy with values of the slope increasing with the decreasing azimuthal acceptance of the trigger. The majority of events selected with full azimuthal acceptance are nonplanar; hence they do not show jet-like event structure. The fraction of planar events is small and remains constant as a function of transverse energy.
120314760
A Study of Jet Like Structure in High Transverse Energy Events Produced in p p Collisions at 400-GeV/c
The properties of events produced with high values of transverse energy in 400-GeV/c pp collisions are presented. The events were collected using the large-acceptance Fermilab multiparticle spectrometer. The fraction of events that are planar when a full-azimuthal-acceptance trigger is used does not increase with transverse energy. However, when additional requirements are applied to the data such as restricting the azimuth or polar-angle acceptance, limiting the particle multiplicity, or requiring dominance of electromagnetic or hadronic energy within an event, the fraction of planar events increases with transverse energy. None of these requirements explicitly impose planar structure and we conclude that the data show an indication for the emergence of jetlike structure. The trend of the data is consistent with the predictions of a QCD model; it cannot be described by an extrapolation of uncorrelated low-p/sub t/ phenomena.