221 research outputs found
Supersymmetric Gauge Theories with an Affine Quantum Moduli Space
All supersymmetric gauge theories based on simple groups which have an affine
quantum moduli space, i.e. one generated by gauge invariants with no relations,
W=0, and anomaly matching at the origin, are classified. It is shown that the
only theories with no gauge invariants (and moduli space equal to a single
point) are the two known examples, SU(5) with 5-bar + 10 and SO(10) with a
spinor. The index of the matter representation must be at least as big as the
index of the adjoint in theories which have a non-trivial relation among the
gauge invariants.Comment: Incorrect proof that theories with constraints must have mu >=
mu(adj) replaced by a correct one (6 pages, uses revtex, amssymb, array
Topology of "white" stars in relativistic fragmentation of light nuclei
In the present paper, experimental observations of the multifragmentation
processes of light relativistic nuclei carried out by means of emulsions are
reviewed. Events of the type of "white" stars in which the dissociation of
relativistic nuclei is not accompanied by the production of mesons and the
target-nucleus fragments are considered.
A distinctive feature of the charge topology in the dissociation of the Ne,
Mg, Si, and S nuclei is an almost total suppression of the binary splitting of
nuclei to fragments with charges higher than 2. The growth of the nuclear
fragmentation degree is revealed in an increase in the multiplicity of singly
and doubly charged fragments with decreasing charge of the non-excited part of
the fragmenting nucleus.
The processes of dissociation of stable Li, Be, B, C, N, and O isotopes to
charged fragments were used to study special features of the formation of
systems consisting of the lightest , d, and t nuclei. Clustering in
form of the He nucleus can be detected in "white" stars via the
dissociation of neutron-deficient Be, B, C, and N isotopes.Comment: 20 pages, 3 figures, 9 tables, conference: Conference on Physics of
Fundamental Interactions, Moscow, Russia, 1-5 Mar 2004.(Author's translation
Plane torsion waves in quadratic gravitational theories
The definition of the Riemann-Cartan space of the plane wave type is given.
The condition under which the torsion plane waves exist is found. It is
expressed in the form of the restriction imposed on the coupling constants of
the 10-parametric quadratic gravitational Lagrangian. In the mathematical
appendix the formula for commutator of the variation operator and Hodge
operator is proved. This formula is applied for the variational procedure when
the gravitational field equations are obtained in terms of the exterior
differential forms.Comment: 3 May 1998. - 11
Electromagnetic dissociation of relativistic B nuclei in nuclear track emulsion
Experimental data on fragmentation channels in peripheral interactions of
B nuclei in nuclear track emulsions are presented. A detailed analysis made
it possible to justify selections of events of the electromagnetic-dissociation
process B Be + \emph{p} and to estimate its cross section. Events of
C peripheral dissociation that were observed in the same exposure are
described.Comment: 12 pages, 10 figures, 4 tables, Published in
Phys.Atom.Nucl.72:690-701,200
Exposure of Nuclear Track Emulsion to a Mixed Beam of Relativistic N, C, and Be Nuclei
A nuclear track emulsion was exposed to a mixed beam of relativistic
N, C, and Be nuclei having a momentum of 2 GeV/ per
nucleon. The beam was formed upon charge exchange processes involving C
primary nuclei and their fragmentation. An analysis indicates that C
nuclei are dominant in the beam and that N nuclei are present in it. The
charge topology of relativistic fragments in the coherent dissociation of these
nuclei is presented.Comment: ISSN 1063-7788, Pleiades Publishing, Ltd., 201
Search for the exotic Resonance in 340GeV/c -Nucleus Interactions
We report on a high statistics search for the resonance in
-nucleus collisions at 340GeV/c. No evidence for this resonance is
found in our data sample which contains 676000 candidates above
background. For the decay channel and the
kinematic range 0.150.9 we find a 3 upper limit for the
production cross section of 3.1 and 3.5 b per nucleon for reactions with
carbon and copper, respectively.Comment: 5 pages, 4 figures, modification of ref. 43 and 4
Differential Transverse Flow in Central C-Ne and C-Cu Collisions at 3.7 GeV/nucleon
Differential transverse flow of protons and pions in central C-Ne and C-Cu
collisions at a beam energy of 3.7 GeV/nucleon was measured as a function of
transverse momentum at the SKM-200-GIBS setup of JINR. In agreement with
predictions of a transversely moving thermal model, the strength of proton
differential transverse flow is found to first increase gradually and then
saturate with the increasing transverse momentum in both systems. While pions
are preferentially emitted in the same direction of the proton transverse flow
in the reaction of C-Ne, they exhibit an anti-flow to the opposote direction of
the proton transverse flow in the reaction of C-Cu due to stronger shadowing
effects of the heavier target in thr whole range of transverse momentum.Comment: 15 pages, 5 figure
QCD in the nuclear medium and effects due to Cherenkov gluons
The equations of in-medium gluodynamics are proposed. Their classical lowest
order solution is explicitly shown for a color charge moving with constant
speed. For nuclear permittivity larger than 1 it describes emission of
Cherenkov gluons resembling results of classical electrodynamics. The values of
the real and imaginary parts of the nuclear permittivity are obtained from the
fits to experimental data on the double-humped structure around the away-side
jet obtained at RHIC. The dispersion of the nuclear permittivity is predicted
by comparing the RHIC, SPS and cosmic ray data. This is important for LHC
experiments. Cherenkov gluons may be responsible for the asymmetry of dilepton
mass spectra near rho-meson, observed in the SPS experiment with excess in the
low-mass wing of the resonance. This feature is predicted to be common for all
resonances. The "color rainbow" quantum effect might appear according to higher
order terms of in-medium QCD if the nuclear permittivity depends on color.Comment: 29 p., 4 figs; for "Phys. Atom. Nucl." volume dedicated to 80th
birthday of L.B. Okun; minor corrections on pp. 11 and 13 in v
Atmospheric Muon Flux at Sea Level, Underground, and Underwater
The vertical sea-level muon spectrum at energies above 1 GeV and the
underground/underwater muon intensities at depths up to 18 km w.e. are
calculated. The results are particularly collated with a great body of the
ground-level, underground, and underwater muon data. In the hadron-cascade
calculations, the growth with energy of inelastic cross sections and pion,
kaon, and nucleon generation in pion-nucleus collisions are taken into account.
For evaluating the prompt muon contribution to the muon flux, we apply two
phenomenological approaches to the charm production problem: the recombination
quark-parton model and the quark-gluon string model. To solve the muon
transport equation at large depths of homogeneous medium, a semi-analytical
method is used. The simple fitting formulas describing our numerical results
are given. Our analysis shows that, at depths up to 6-7 km w. e., essentially
all underground data on the muon intensity correlate with each other and with
predicted depth-intensity relation for conventional muons to within 10%.
However, the high-energy sea-level data as well as the data at large depths are
contradictory and cannot be quantitatively decribed by a single nuclear-cascade
model.Comment: 47 pages, REVTeX, 15 EPS figures included; recent experimental data
and references added, typos correcte
Heavy Baryon Specroscopy from the Lattice
The results of an exploratory lattice study of heavy baryon spectroscopy are
presented. We have computed the full spectrum of the eight baryons containing a
single heavy quark, on a lattice at , using an
-improved fermion action. We discuss the lattice baryon operators and
give a method for isolating the contributions of the spin doublets
, and to the correlation
function of the relevant operator. We compare our results with the available
experimental data and find good agreement in both the charm and the beauty
sectors, despite the long extrapolation in the heavy quark mass needed in the
latter case. We also predict the masses of several undiscovered baryons. We
compute the \Lambda-\mbox{pseudoscalar meson} and mass
splittings. Our results, which have errors in the range , are in good
agreement with the experimental numbers. For the mass
splitting, we find results considerably smaller than the experimental values
for both the charm and the beauty baryons, although in the latter case the
experimental results are still preliminary. This is also the case for the
lattice results for the hyperfine splitting for the heavy mesons.Comment: 31 pages LaTex, with postscript figures include
- âŠ