121567945
An optical model consistency condition between the regeneration phase and the real parts of the KON forward scattering amplitudes
Abstract Using just the magnitude of the regeneration amplitude we show that both the regeneration phase, ϕ r , and the sum of the ratios of the real to imaginary parts of the K O N forward scattering amplitudes, γ pn , can be determined for nuclei with zero or moderate neutron excess. We find: ϕ r = (43.5 ± 2.5) o ; γ pn = −0.73 ± 0.1 + 1.7 γ pn 〈 2.7 GeV /c 〉 = −0.65 ± 0.07 + 1.6 γ pn 〈 4.5 GeV /c 〉 , where γ pn is corresponding quantity for K O N scattering. Applications to regeneration in hydrogen and the ϕ-meson are discussed.
124802336
CYCLOTRON ORBITS: A 709 RAY-TRACE PROGRAM FOR CYLIN-DRICALLY SYMMETRIC MAGNETIC FIELDS
CYCLOTRON ORBITS is a 709 program for tracing secondary beams out of a cylindrically symmetric magnetic field. Development of a 6-by-6 transfer matrix allows one to couple to external quadrupole and bending magnets. (auth)
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.
121567945
An optical model consistency condition between the regeneration phase and the real parts of the KON forward scattering amplitudes
Abstract Using just the magnitude of the regeneration amplitude we show that both the regeneration phase, ϕ r , and the sum of the ratios of the real to imaginary parts of the K O N forward scattering amplitudes, γ pn , can be determined for nuclei with zero or moderate neutron excess. We find: ϕ r = (43.5 ± 2.5) o ; γ pn = −0.73 ± 0.1 + 1.7 γ pn 〈 2.7 GeV /c 〉 = −0.65 ± 0.07 + 1.6 γ pn 〈 4.5 GeV /c 〉 , where γ pn is corresponding quantity for K O N scattering. Applications to regeneration in hydrogen and the ϕ-meson are discussed.
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.
119271491
Searching for string resonances in $e^+e^-$ and $\gamma \gamma$ collisions
If the fundamental mass scale of superstring theory is as low as few TeVs, the massive modes of vibrating strings, Regge excitations, will be copiously produced at the Large Hadron Collider (LHC). We discuss the complementary signals of low mass superstrings at the proposed electron-positron facility (CLIC), in e^+e^- and \gamma \gamma collisions. We examine all relevant four-particle amplitudes evaluated at the center of mass energies near the mass of lightest Regge excitations and extract the corresponding pole terms. The Regge poles of all four-point amplitudes, in particular the spin content of the resonances, are completely model independent, universal properties of the entire landscape of string compactifications. We show that \gamma \gamma \to e^+ e^- scattering proceeds only through a spin-2 Regge state. We estimate that for this particular channel, string scales as high as 4 TeV can be discovered at the 11\sigma level with the first fb^{-1} of data collected at a center-of-mass energy \approx 5 TeV. We also show that for e^+e^- annihilation into fermion-antifermion pairs, string theory predicts the precise value, equal 1/3, of the relative weight of spin 2 and spin 1 contributions. This yields a dimuon angular distribution with a pronounced forward-backward asymmetry, which will help distinguishing between low mass strings and other beyond the standard model scenarios.
122963598
Fractionally Charged Color Singlet Fermions in a Grand Unified Theory
18903804
Exact nonperturbative unitary amplitudes for 1 → 8 transitions in a field theoretic model
Abstract We present a quantum mechanical model with an infinite number of (discrete) degrees of freedom, which can serve as a laboratory for multiparticle production in a collision. There is a cubic coupling between modes without, however, any problems associated with unstable ground states. The model is amenable to precise numerical calculations of nonperturbative 1 → N transition amplitudes. On an ordinary workstation, time and memory limitations effectively restrict N to be ⩽ 8, and we present results for this case. We find (1) that there is reasonable period of time for which there is a constant rate for the 1 → 8 transition; (2) at the end of the linear period, the eight particle amplitude attains a maximum value | A 8 | max which is about 3–4 orders of magnitude larger than the comparable amplitude for excitation of the N =8 state in the anharmonic oscillator; (3) for values of the coupling in the region where the Born approximation fails, the amplitude is much larger than the naive estimates A 8≅exp(−1/ g 2 ) or exp(−8); it is more like A 8 ∼exp(−0.20/ g 2 ).
123378872
New sum rule for photoproduction amplitudes based on local current commutators
117808653
Black hole chromosphere at the CERN LHC
If the scale of quantum gravity is near a TeV, black holes will be copiously produced at the CERN LHC. In this work we study the main properties of the light descendants of these black holes. We show that the emitted partons are closely spaced outside the horizon, and hence they do not fragment into hadrons in vacuum but more likely into a kind of quark-gluon plasma. Consequently, the thermal emission occurs far from the horizon, at a temperature characteristic of the QCD scale. We analyze the energy spectrum of the particles emerging from the ``chromosphere,'' and find that the hard hadronic jets are almost entirely suppressed. They are replaced by an isotropic distribution of soft photons and hadrons, with hundreds of particles in the GeV range. This provides a new distinctive signature for black hole events at LHC.