Single Spin Asymmetries in Proton-Proton and Proton-Neutron Scattering at 820 GeV

The physics case is summarised for the investigation of high energy spin phenomena by placing an internal polarised target into HERA's unpolarised proton beam. The luminosity and experimental sensitivity are discussed. Estimating the physics reach of single spin asymmetries in different final states reveals a considerable physics potential in testing the spin sector of perturbative QCD.Comment: 10 pages + 5 uuencoded ps figures, late

DIS structure functions and the double-spin asymmetry in rho(0) electroproduction within a Regge approach

The proton, neutron and deuteron structure functions F2(x,Q2) and g1(x,Q2), measured at intermediate Q2, are analyzed within a Regge approach. This analysis serves to fix the parameters of this scheme which are then used to calculate, in a unified Regge approach, the properties of ρ0 meson electroproduction on the proton and the deuteron. In this way, the double-spin asymmetry observed at HERMES in ρ0 electroproduction on the proton, can be related to the anomalous behavior of the flavor-singlet part of the spin-dependent structure function g1(x,Q2) at small x

Molecular analysis of desmoid tumors with a high-density single-nucleotide polymorphism array identifies new molecular candidate lesions

Background: Desmoid tumors are neoplastic proliferations of connective tissues. The mutation status of the gene coding for catenin (cadherin-associated protein) beta 1 (CTNNB1) and trisomy 8 on the chromosomal level have been described to have prognostic relevance. Patients and Methods: In order to elucidate new molecular mechanisms underlying these tumors, we carried out a molecular analysis with a genome-wide human high-density single-nucleotide polymorphism (SNP) array, in 9 patients. Results: Single samples showed numerical aberrations on chromosomes (Chrs) 20 and 6 with either trisomy 20 or monosomy 6. No trisomy 8 could be detected. Recurrent heterozygous deletions were found in Chr 5q (including the APC gene locus, n = 3) and Chr 8p23 (n = 4, containing coding regions for the potential tumor suppressor gene CSMD1). This novel deletion in 8p23 showed an association with local recurrence. In addition, structural chromosomal changes (gain of Chrs 8 and 20) were found in a minority of cases. Conclusion: The genomic alteration affecting the candidate gene CSMD1 could be important in the development of desmoid tumors

RF-Separated Beam Project for the M2 Beam Line at CERN

Within the framework of the Physics Beyond Colliders initiative at CERN, discussions are underway on the feasibility of producing radio-frequency (RF) separated beams for Phase-2 of the AMBER experiment at the M2 beam line in the North experimental area of the CERN SPS. The technique of RF separation is applied to enrich the content of a certain particle type within a beam consisting of different species at the same momentum. It relies on the fact that each particle type has a different velocity, decreasing with rest mass. The successor of the COMPASS experiment, AMBER, requires for its Phase-2 measurements high-intensity, high-purity kaon (and antiproton) beams, which cannot be delivered with the currently existing conventional M2 beam line. The present contribution introduces the principle of RF separation and explains its dependence on different parameters of beam optics and hardware. The first examination of potential showstoppers for the RF-separated beam implementation is presented, based on the particle production rates, beam line transmission for specific optics settings, limitations for overall beam intensity and purity posed by beam line acceptance and radiation protection. Different beam optics settings have been examined, providing either focused or parallel beams inside the RF cavities. The separation and transmission capability of the different optics settings for realistic characteristics of RF cavities are discussed and the preliminary results of the potential purity and intensity of the RF-separated beam are presented. They illustrate the high importance of an RF-separated kaon beam for many of the AMBER Phase-2 data taking programs, such as spectroscopy, prompt-photon production, Primakoff reactions and kaon charge-radius measurement