PVDIS at 12 GeV at JLab

In 1956 Lee and Yang suggested that parity might be violated and, if nature were so, they further described a recipe on how to exploit that broken symmetry to measure the muon??s magnetic moment. Of course parity violation was very soon confirmed in the weak interactions and many generations of experiments since then have led to a determination of ?? _?? to better than part-per-billion precision. A new experiment proposed for Fermilab is planned to push this precision further still, being motivated by the sensitive comparison of measurement to exquisite theory. We report on the current comparison, which exceeds three standard deviations, and the plans and promise for the future experimental effort.     

CRYRING at the LSR at FLAIR

FLAIR will be the next-generation facility for physics with low-energy antiprotons, providing antiprotons at energies from tens of MeV down to rest. It will also offer unique possibilities for physics with highly charged ions at very low energies. The FLAIR facility will have two deceleration rings, the LSR which will decelerate antiprotons to 300 keV and the USR which will bring them down further to 20 keV. The LSR will consist of the present CRYRING at the Manne Siegbahn Laboratory. During the next few years, CRYRING will be modified with respect to injection and extraction, to allow injection of 30 MeV antiprotons and to provide it with both fast (single-turn) and slow (resonant) extraction at a variable energy. We here describe plans and preparations for the transfer of CRYRING to FLAIR, giving, in particular, an overview of new components for injection and extraction.     

Multi-lepton production at high transverse momentum at HERA

A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb⁻¹. The number of observed events has been compared with the prediction from the Standard Model, searching for possible deviations, especially for multi-lepton events with invariant mass larger than 100 GeV. Good agreement with the Standard Model has been observed. Total and differential cross sections for di-lepton production have been measured in a restricted phase space dominated by photon–photon collisions.     

Polarized proton collisions at 205 GeV at RHIC

The Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions. Polarized protons were first accelerated to the record energy of 205 GeV in RHIC with a significant polarization measured at top energy in 2005. This Letter presents the results and discusses the sensitivity of the polarization survival to orbit distortions.     

Elastic Wave Reflection at the Interface at Preset Stresses

Russian Physics Journal - The problem of elastic wave reflection at the interface at preset constant stresses is discussed. Under the conditions where the reflection laws are fulfilled, analytical...     

Atomic Physics Studies at the Gamma Factory at CERN

The Gamma Factory initiative proposes to develop novel research tools at CERN by producing, accelerating, and storing highly relativistic, partially stripped ion beams in the SPS and LHC storage rings. By exciting the electronic degrees of freedom of the stored ions with lasers, high-energy narrow-band photon beams will be produced by properly collimating the secondary radiation that is peaked in the direction of ions' propagation. Their intensities, up to 10¹⁷ photons per second, will be several orders of magnitude higher than those of the presently operating light sources in the particularly interesting γ–ray energy domain reaching up to 400 MeV. This article reviews opportunities that may be afforded by utilizing the primary beams for spectroscopy of partially stripped ions circulating in the storage ring, as well as the atomic-physics opportunities made possible by the use of the secondary high-energy photon beams. The Gamma Factory will enable ground-breaking experiments in spectroscopy and novel ways of testing fundamental symmetries of nature.     

Graphite at high pressures: Pseudomelting at 44 GPa

Abstract

The Raman spectra comparative study of graphite-like modifications of carbon: monocrystalline graphite, pyrolytic graphite and amorphous (glassy) carbon was performed at high pressures and room temperature. At P = 44 GPa an abrupt broadening of Raman bands of pyrolytic graphite and glassy carbon was observed. The same process in monocrystalline graphite occures continuously from 23 to 44 GPa and for higher pressures the Raman spectra of all three substances under study become practically indistinguishable from one another and from that of amorphous carbon (a-C) at the same pressure. This result is ascribed to the formation at these pressures of the dence amorphous carbon modification.     

New look at thermodynamics of gas and at clusterization

In the paper, by using the example of a rigorous formulation and rigorous proof of the Maxwell distribution, estimates for the distribution in dependence of the parameter N (the number of particles) are established. Further, the problem concerning the creation of dimers in classical gas is regarded as an analog of Bose condensation, and estimates for the lower level of the analog of Bose condensation are proved. The relationship between this level and the theory of “capture” in the scattering problem corresponding to interaction in the form of Lennard-Jones potential is clarified. The equation of state of a nonideal gas as a result of pairwise interaction of particles in the Lennard-Jones and Kihara models is derived. New quantum equations for the transfer of neutral gas consisting of particles with evenly and oddly many neutrons in capillaries and nanotubes are also presented. To the memory of my teacher in number theory, Professor Anatolii Karatsuba     

Experiments on the study of the deuteron-proton interactions at intermediate energies at Internal Target at Nuclotron

The experimental program on the study of deuteron-proton interaction at Internal Target at Nuclotron is discussed. Recent results obtained for dp-elastic scattering and dp-breakup reactions at intermediate energies are presented. The status of the DSS setup upgrade is reported.     

Droplet traffic at a simple junction at low capillary numbers

We report that, when a train of confined droplets flowing through a channel reaches a junction, the droplets either are alternately distributed between the different outlets or all collect into the shortest one. We argue that this behavior is due to the hydrodynamic feedback of droplets in the different outlets on the selection process occurring at the junction. A "mean field" model, yielding semiquantitative results, offers a first guide to predict droplet traffic in branched networks.     

Measurement of dijet photoproduction at high transverse energies at HERA

The cross section for dijet photoproduction at high transverse energies is presented as a function of the transverse energies and the pseudorapidities of the jets. The measurement is performed using a sample of ep-interactions corresponding to an integrated luminosity of 6.3 pb, recorded by the ZEUS detector. Jets are defined by applying a -clustering algorithm to the hadrons observed in the final state. The measured cross sections are compared to next-to-leading order QCD calculations. In a kinematic regime where theoretical uncertainties are expected to be small, the measured cross sections are higher than these calculations. Received: 18 May 1999 / Published online: 14 October 1999     

Hadron production at forward rapidity in nuclear collisions at RHIC

The main experimental results obtained by the BRAHMS experiment at Relativistic Heavy Ion Collider (RHIC) for Au+Au collisions at \(\sqrt {s_{NN} } \) =62.4, 200 GeV and d+Au collisions at \(\sqrt {s_{NN} } \) = 200GeV are presented. The m _T spectra and the Gaussian-like rapidity densities of produced pions and kaons in Au+Au central collisions at \(\sqrt {s_{NN} } \) = 200 are GeV shown, and their rapidity densities are compared with results from models. The net-proton yield in the same system is compared with that from AGS and SPS energies to study the high energy collision scenario-transparency and stopping. The rapidity, energy and centrality dependence of the nuclear modification factors in both systems are compared with models to differentiate between the initial and final state effect.     

Sleptons at post-WMAP benchmark points at LHC (CMS)

We study the possibility of detecting sleptons at post-WMAP benchmark points at LHC (CMS). We find that, at L_tot = 30 fb^?1, it would be possible to detect sleptons at points B, C, D, G. We also investigate the production and decays of right and left sleptons separately. We find that, at L_tot = 30 fb^?1, it would be possible to detect right sleptons with a mass up to 200 GeV and left ones with a mass up to 300 GeV.