Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

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Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

We provide an updated assessment of the power of the Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at the TeV scale, via the associated gamma-ray signal from pair-annihilating dark matter particles in the region around the Galactic centre. We find that CTA will open a new window of discovery potential, significantly extending the range of robustly testable models given a standard cuspy profile of the dark matter density distribution. Importantly, even for a cored profile, the projected sensitivity of CTA will be sufficient to probe various well-motivated models of thermally produced dark matter at the TeV scale. This is due to CTA's unprecedented sensitivity, angular and energy resolutions, and the planned observational strategy. The survey of the inner Galaxy will cover a much larger region than corresponding previous observational campaigns with imaging atmospheric Cherenkov telescopes. CTA will map with unprecedented precision the large-scale diffuse emission in high-energy gamma rays, constituting a background for dark matter searches for which we adopt state-of-the-art models based on current data. Throughout our analysis, we use up-to-date event reconstruction Monte Carlo tools developed by the CTA consortium, and pay special attention to quantifying the level of instrumental systematic uncertainties, as well as background template systematic errors, required to probe thermally produced dark matter at these energies

Detailed gamma-ray spectroscopy of Cr-55 and Cr-56: confirmation of the subshell closure at N=32

The nuclei Cr-55,Cr-56 were populated to high spin following the reaction Ca-48(B-11,pxn)Cr58-x at a beam energy of 35-40 MeV. The level scheme of Cr-55 has been confirmed and extended to J(pi)=25+/2. The level scheme of Cr-56 has been extended to J=13. The spins and parity of the majority of levels have been determined unambiguously for the first time. The first firm evidence for an intruder band based on the nug(9/2) orbital has been observed in Cr-55. In Cr-56, the position of the first 4(+) state has been determined unambiguously and the presence of a subshell closure at N = 32 has been confirmed on the basis of the E-41(+)/E-21(+) systematics. The properties of both nuclei are compared with total Routhian surface calculations and with previous predictions of subshell closures at N = 32 and 34. The systematics in the region are discussed in terms of the strong nuf(5/2)-pif(7/2) interaction and its effect on the underlying single-particle structure.Physics, NuclearSCI(E)34ARTICLE3null6

Amino-terminal domains of c-myc and N-myc proteins mediate binding to the retinoblastoma gene product

The proteins encoded by the myc gene family are involved is the control of cell proliferation and differentiation, and aberrant expression of myc proteins has been implicated in the genesis of a variety of neoplasms. In the carboxyl terminus, myc proteins have two domains that encode a basic domain/helix-loop-helix and a leucine zipper motif, respectively. These motifs are involved both in DNA binding and in protein dimerization. In addition, myc protein family members share several regions of highly conserved amino acids in their amino termini that are essential for transfornation. We report here that an N-terminal domain present in both the c-myc and N-myc proteins mediates binding to the retinoblastoma gene product PRb. We show that the human papilloma virus E7 protein competes with c-myc for binding to pRb, indicating that these proteins share overlapping binding sites on pRb. Furthermore, a mutant Rb protein from a human tumour cell line that carried a 35-amino-acM deletion in its C terminus failed to bind to c-myc. Our results suggest that c-myc and pRb cooperate through direct binding to central cell proliferation