169 research outputs found
Measurements of spin rotation parameter A in pion-proton elastic scattering at 1.62 GeV/c
The ITEP-PNPI collaboration presents the results of the measurements of the
spin rotation parameter A in the elastic scattering of positive and negative
pions on protons at P_beam = 1.62 GeV/c. The setup included a
longitudinally-polarized proton target with superconductive magnet, multiwire
spark chambers and a carbon polarimeter with thick filter. Results are compared
to the predictions of partial wave analyses. The experiment was performed at
the ITEP proton synchrotron, Moscow.Comment: 7 pages, 3 figures. To be published in Phys. Lett.
Chaos in the one-dimensional gravitational three-body problem
We have investigated the appearance of chaos in the 1-dimensional Newtonian
gravitational three-body system (three masses on a line with pairwise
potential). We have concentrated in particular on how the behavior changes when
the relative masses of the three bodies change (with negative total energy).
For two mass choices we have calculated 18000 full orbits (with initial states
on a lattice on the Poincar\'e section) and obtained dwell time
distributions. For 105 mass choices we have calculated Poincar\'e maps for
starting points. Our results show that the Poincar\'e section
(and hence the phase space) divides into three well defined regions with orbits
of different characteristics: 1) There is a region of fast scattering, with a
minimum of pairwise collisions and smooth dependence on initial values. 2) In
the chaotic scattering region the interaction times are longer, and both the
interaction time and the final state depend sensitively on the starting point
on the Poincar\'e section. For both 1) and 2) the initial and final states
consists of a binary + single particle. 3) The third region consists of
quasiperiodic orbits where the three masses are bound together forever. At the
center of the quasiperiodic region there is the periodic Schubart orbit, whose
stability turns out to correlate strongly with the global behavior.Comment: 24 pages of text (REVTEX 3.0) + 21 pages of figures. Figures are only
available in paper form, ask for a preprint from the author
Lebedev physical institute radiation complex – current status and new concepts
Multipurpose radiation complex is the result of long- term permanent development of new instrumentation at the Lebedev Physical Institute. This is stand-alone large facility designed for fundamental and applied research that had been started from the high current racetrack microtron project in the mid of seventies and has been completed by commissioning of far infrared FEL nowadays. Current status of the radiation complex including research as well as linac and FEL performance improvement is discussed in paper presented followed by new ideas in further facility development and application
Weighted azimuthal asymmetries in a diquark spectator model
We analytically calculate weighted azimuthal asymmetries in semi-inclusive
lepton-nucleon deep-inelastic scattering and Drell-Yan processes, using
transverse-momentum-dependent partonic densities obtained in a diquark
spectator model. We compare the asymmetries with available preliminary
experimental data, in particular for the Collins and the Sivers effect. We make
predictions for other cases of interest in running and planned experiments.Comment: 21 pages, 13 (multiple) figures in eps format, RevTeX
Membranes with a boundary
We investigate the recently developed theory of multiple membranes. In
particular, we consider open membranes, i.e. the theory defined on a membrane
world volume with a boundary. We first restrict our attention to the gauge
sector of the theory. We obtain a boundary action from the Chern-Simons terms.
Secondly, we consider the addition of certain boundary terms to various
Chern-Simons theories coupled to matter. These terms ensure the full bulk plus
boundary action has the correct amount of supersymmetry. For the ABJM model,
this construction motivates the inclusion of a boundary quartic scalar
potential. The boundary dynamics obtained from our modified theory produce
Basu-Harvey type equations describing membranes ending on a fivebrane. The
ultimate goal of this work is to throw light on the theory of fivebranes using
the theory of open membranes.Comment: 48 pages, Latex, v2 references adde
Entropy and Quantum Kolmogorov Complexity: A Quantum Brudno's Theorem
In classical information theory, entropy rate and Kolmogorov complexity per
symbol are related by a theorem of Brudno. In this paper, we prove a quantum
version of this theorem, connecting the von Neumann entropy rate and two
notions of quantum Kolmogorov complexity, both based on the shortest qubit
descriptions of qubit strings that, run by a universal quantum Turing machine,
reproduce them as outputs.Comment: 26 pages, no figures. Reference to publication added: published in
the Communications in Mathematical Physics
(http://www.springerlink.com/content/1432-0916/
Renormalization of the mass gap
The full gluon propagator relevant for the description of the truly
non-perturbative QCD dynamics, the so-called intrinsically non-perturbative
gluon propagator has been derived in our previous work. It explicitly depends
on the regularized mass gap, which dominates its structure at small gluon
momentum. It is automatically transversal in a gauge invariant way. It is
characterized by the presence of severe infrared singularities at small gluon
momentum, so the gluons remain massless, and this does not depend on the gauge
choice. In this paper we have shown how precisely the renormalization program
for the regularized mass gap should be performed. We have also shown how
precisely severe infrared singularities should be correctly treated. This
allowed to analytically formulate the exact and gauge-invariant criteria of
gluon and quark confinement. After the renormalization program is completed,
one can derive the gluon propagator applicable for the calculation of physical
observables processes, etc., in low-energy QCD from first principles.Comment: 16 pages, no figures, no tables, some minor changes are introduce
Multimessenger astronomy with the Einstein Telescope
Gravitational waves (GWs) are expected to play a crucial role in the
development of multimessenger astrophysics. The combination of GW observations
with other astrophysical triggers, such as from gamma-ray and X-ray satellites,
optical/radio telescopes, and neutrino detectors allows us to decipher science
that would otherwise be inaccessible. In this paper, we provide a broad review
from the multimessenger perspective of the science reach offered by the third
generation interferometric GW detectors and by the Einstein Telescope (ET) in
particular. We focus on cosmic transients, and base our estimates on the
results obtained by ET's predecessors GEO, LIGO, and Virgo.Comment: 26 pages. 3 figures. Special issue of GRG on the Einstein Telescope.
Minor corrections include
Transverse Momentum Dependent Parton Distribution/Fragmentation Functions at an Electron-Ion Collider
We present a summary of a recent workshop held at Duke University on Partonic
Transverse Momentum in Hadrons: Quark Spin-Orbit Correlations and Quark-Gluon
Interactions. The transverse momentum dependent parton distribution functions
(TMDs), parton-to-hadron fragmentation functions, and multi-parton correlation
functions, were discussed extensively at the Duke workshop. In this paper, we
summarize first the theoretical issues concerning the study of partonic
structure of hadrons at a future electron-ion collider (EIC) with emphasis on
the TMDs. We then present simulation results on experimental studies of TMDs
through measurements of single spin asymmetries (SSA) from semi-inclusive
deep-inelastic scattering (SIDIS) processes with an EIC, and discuss the
requirement of the detector for SIDIS measurements. The dynamics of parton
correlations in the nucleon is further explored via a study of SSA in D (`D)
production at large transverse momenta with the aim of accessing the unexplored
tri-gluon correlation functions. The workshop participants identified the SSA
measurements in SIDIS as a golden program to study TMDs in both the sea and
valence quark regions and to study the role of gluons, with the Sivers
asymmetry measurements as examples. Such measurements will lead to major
advancement in our understanding of TMDs in the valence quark region, and more
importantly also allow for the investigation of TMDs in the sea quark region
along with a study of their evolution.Comment: 44 pages 23 figures, summary of Duke EIC workshop on TMDs accepted by
EPJ
Colliders and Cosmology
Dark matter in variations of constrained minimal supersymmetric standard
models will be discussed. Particular attention will be given to the comparison
between accelerator and direct detection constraints.Comment: Submitted for the SUSY07 proceedings, 15 pages, LaTex, 26 eps figure
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