119086153
p-Branes and the GZK paradox
Abstract In spacetimes with asymmetric extra dimensions, cosmic neutrino interactions may be extraordinarily enhanced by p -brane production. Brane formation and decay may then initiate showers deep in the Earth's atmosphere at rates far above the standard model rate. We explore the p -brane discovery potential of cosmic ray experiments. The absence of deeply penetrating showers at AGASA already provides multi-TeV bounds on the fundamental Planck scale that significantly exceed those obtained from black hole production in symmetric compactification scenarios. This sensitivity will be further enhanced at the Auger observatory. We also examine the possibility that p -brane formation resolves the GZK paradox. For flat compactifications, astrophysical bounds exclude this explanation. For warped scenarios, a solution could be consistent with the absence of deep showers only for extra dimensions with fine-tuned sizes well below the fundamental Planck length. In addition, it requires moderately penetrating showers, so far not reported, and ∼100% modifications to standard model phenomenology at 100 GeV energies.
119056773
THE MYSTERIOUS ULTRAHIGH ENERGY COSMIC RAY CLUSTERING
We examine the correlation between compact radio quasars (redshifts in the range z=0.3–2.2) and the arrival direction of ultrahigh energy cosmic rays forming clusters. Our Monte Carlo simulation reveals a statistically significant correlation on the AGASA sample: the chance probability of this effect being less than 1%. The implications of this result on the origin of ultrahigh energy cosmic rays are discussed.
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.
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
123379602
COUPLING AND RECOUPLING OF RELATIVISTIC STATES. II. NOTE ON THE SYSTEMATICS OF MANY PARTICLES SYSTEMS
Abstract : The direct product of many irreducible representations of the Poincare group is discussed. A procedure is suggested for the decomposition in the canonical scheme, which is not an iteration of the 2-particles method. Also, it is independent of the c.m.s. Corresponding expression for S-matrix elements of many particle processes is given. The properties of the invariant functions associated with elastic scattering in case of parity, time reversal and crossing symmetries is discussed, as well as in case of identical particles. (Author)
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.
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.
118297532
A Study of hadronic final states produced in association with high pT jets and high - mass dimuons