18 research outputs found
Target mass effects in polarized deep-inelastic scattering
We present a computation of nucleon mass corrections to nucleon structure
functions for polarized deep-inelastic scattering. We perform a fit to existing
data including mass corrections at first order in and we study the
effect of these corrections on physically interesting quantities. We conclude
that mass corrections are generally small, and compatible with current
estimates of higher twist uncertainties, when available.Comment: 22 pages Latex, uses epsfig.sty, 10 eps figures include
Kink-induced symmetry breaking patterns in brane-world SU(3)^3 trinification models
The trinification grand unified theory (GUT) has gauge group SU(3)^3 and a
discrete symmetry permuting the SU(3) factors. In common with other GUTs, the
attractive nature of the fermionic multiplet assignments is obviated by the
complicated multi-parameter Higgs potential apparently needed for
phenomenological reasons, and also by vacuum expectation value (VEV)
hierarchies within a given multiplet. This motivates the rigorous consideration
of Higgs potentials, symmetry breaking patterns and alternative symmetry
breaking mechanisms in models with this gauge group. Specifically, we study the
recently proposed ``clash of symmetries'' brane-world mechanism to see if it
can help with the symmetry breaking conundrum. This requires a detailed
analysis of Higgs potential global minima and kink or domain wall solutions
interpolating between the disconnected global minima created through
spontaneous discrete symmetry breaking. Sufficiently long-lived metastable
kinks can also be considered. We develop what we think is an interesting,
albeit speculative, brane-world scheme whereby the hierarchical symmetry
breaking cascade, trinification to left-right symmetry to the standard model to
colour cross electromagnetism, may be induced without an initial hierarchy in
vacuum expectation values. Another motivation for this paper is simply to
continue the exploration of the rich class of kinks arising in models that are
invariant under both discrete and continuous symmetries.Comment: 12 pages, RevTex, references adde
Chromomagnetism in nuclear matter
Quarks are color charged particles. Due to their motion there is a strong
possibility of generation of color magnetic field. It is shown that however
hadrons are color singlet particles they may have non-zero color magnetic
moment. Due to this color magnetic moment hadrons can show color interaction.
In this paper we have studied the chromomagnetic properties of nuclear matter.Comment: 6 pages, 1 figure, accepted for publication in Int. J. Theor. Phy
Q-balls in Underground Experiments
In this paper we present some features of Q-balls and we discuss their
interactions with matter, and their energy losses in the Earth, for a large
range of velocities. These calculations are used to compute the fractional
geometrical acceptance of the MACRO detector. Furthermore a systematic analysis
of the energy losses of Q-balls in three types of detectors is investigated.
More specifically we have computed the light yield in liquid scintillators, the
ionization in streamer tubes and the Restricted Energy Loss in the CR39 nuclear
track detectors.Comment: 7 pages, 4 PS figures included with epsfig, uses espcrc2.sty Talk
given at the Sixth Topical Seminar on Neutrino and Astroparticle Physics, San
Miniato, Italy, 17-21 May 199
Tau neutrino deep inelastic charged current interactions
The nu_mu -> nu_tau oscillation hypothesis will be tested through nu_tau
production of tau in underground neutrino telescopes as well as long-baseline
experiments. We provide the full QCD framework for the evaluation of tau
neutrino deep inelastic charged current (CC) cross sections, including
next-leading-order (NLO) corrections, charm production, tau threshold, and
target mass effects in the collinear approximation. We investigate the
violation of the Albright-Jarlskog relations for the structure functions F_4,5
which occur only in heavy lepton (tau) scattering. Integrated CC cross sections
are evaluated naively over the full phase space and with the inclusion of DIS
kinematic cuts. Uncertainties in our evaluation based on scale dependence, PDF
errors and the interplay between kinematic and dynamical power corrections are
discussed and/or quantified.Comment: 28 pages, 10 figure
Precision physics at a neutrino factory
Neutrino beams of unprecedented flux could be produced in a Neutrino Factory from muon decays. In the vicinity of the storage ring, short baseline experiments would perform a new class of precise tests of the theory and original deep-inelastic-scattering (DIS) studies. Thanks to the availability of high energy νe and νe, the long baseline experiments will be capable of very precise measurements of neutrino oscillations, including ability to solve parameter ambiguities and study of leptonic CP violation, for any value of the mixing angle θ13 above a fraction of a degree. Finally, the Neutrino Factory is the first step towards muon colliders
Implications of parity violation in atoms for gauge theories
The knowledge to be gained on neutral currents from parity-violating observables in heavy atoms is studied. After isolating the relevant couplings, the major part of the analysis is done within the framework ofSU 2 ⊗U 1 unified gauge theories of weak and electromagnetic interactions. The leptonic and hadronic sectors of these models are studied separately, by means of the available information from neutrino physics, to impose restrictions on the mass of the neutral intermediate boson and on the unification angle. The observable in atoms, which provides a link between the two sectors, is found to be powerful in discriminating among models