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.
18810345
Lepton flavor violation in SUSY SO(10) with predictive Yukawa texture.
We analyze the scalar lepton mass matrices in a supersymmetric SO(10) grand unified model with soft SUSY-breaking terms generated at the Planck scale and a Georgi-Jarlskog Yukawa texture at the GUT scale induced by higher dimensional operators. This model predicts lepton flavor violation. The predictive features of the Georgi-Jarlskog texture are used to estimate branching ratios for the radiative decays {ital e}{sub {ital a}}{r_arrow}{ital e}{sub {ital b}}+{gamma}, and we find rates that could provide an experimental test for this kind of model. {copyright} {ital 1996 The American Physical Society.}
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.
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.
36230741
Nonperturbative multiparticle tree graphs in the standard electroweak theory.
I present a lower bound for the cross section at the tree level for {ital f}{sub {ital R}{bar f}{ital L}}{r arrow}{ital NZ} to lowest order in the hypercharge coupling {ital g}{prime}. It is seen that the cross section grows like {ital g}{sup 2{ital N}N} , and hence violates {ital J}=1 unitarity for large enough {ital N}{approx gt}(const/{ital g}{sup 2}). This phenomenon occurs in the kinematic region where coherence among {similar to}{ital N} graphs is possible: the vector mesons are nonrelativistic and they all have the same or a small fixed number of polarization vectors. The argument is then extended to the process {ital f}{sub {ital R}{bar f}{ital L}}{r arrow}(({ital N}/3){ital W}{sup +},({ital N}/3){ital W}{sup {minus}},({ital N}/3){ital Z}), and finally to the general case of an arbitrary initial state, and a final state containing a large number of nonrelativistic {ital W}{sup {plus minus}}'s and {ital Z}'s. The result involves only the gauge couplings, and is independent of the size of the quartic scalar coupling. There is qualitative similarity with the result found previously for tree graphs in {lambda}{phi}{sup 4} theory.
3112178
Auger test of the Cen A model of highest energy cosmic rays.
If, as recently proposed by Farrar and Piran, Cen A is the source of cosmic rays detected above the Greisen-Zatsepin-Kuz'min cutoff, neutrons are approximately 140 more probable than protons to be observed along its line of sight. This is because the proton flux is rendered nearly isotropic by O(microG) intergalactic magnetic fields. With the anticipated aperture of the Southern Auger Observatory, one may expect on the order of 2 neutron events /year above 10(20) eV in the line of sight of Cen A.
102780453
ELASTICALLY SCATTERED POLARIZATION OF 40-MeV PROTONS FROM DEUTERIUM
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.