7,285 research outputs found
The virtual photon structure at HERA
An overview is given of the ongoing measurement at HERA of the parton
structure of the photon, as a function of its virtuality. Preliminary ZEUS
results show disagreement with an NLO QCD calculation.Comment: To appear in Proc. International Conference on the Structure and
Interactions of the Photon, Frascati, April 200
Detection of new states using forward proton tagging at the LHC
This talk summarises the ongoing proposals to upgrade the ATLAS and CMS
detectors by the installation of forward silicon detector systems close to the
beam line at distances of approximately 220 m and 420 m from the respective
Interaction Points. The physics motivation is outlined, with emphasis on
detection of Higgs and Supersymmetric states, and some of the aspects of the
apparatus and its performance are briefly described.Comment: For ICHEP XXXIV Conference Proceedings. 4 pages. v2 has updated refs
and minor corrections. v3 has cosmetic layout change
Prompt photon, Drell-Yan and Bethe-Heitler processes in hard photoproduction
We present prospects and requirements for the study at HERA of hard photon
processes which generate high photons in the final state, and processes
which generate Drell-Yan lepton pairs.Comment: 6 pages, 3 embedded figures. To appear in the proceedings of the
workshop "Future physics at HERA
Resonance Contributions to Photoproduction on Protons Found Using Dispersion Relations and an Isobar Model
The contributions of the resonances , ,
, , , , ,
to are found from the data on cross
sections, beam and target asymmetries using two approaches: fixed-t dispersion
relations and an isobar model. Utilization of the two approaches and comparison
of the results obtained with different parametrizations of the resonance
contributions allowed us to make conclusions about the model-dependence of
these contributions. We conclude that the results for the contributions of the
resonances , , to corresponding
multipole amplitudes are stable. With this the results for and
, combined with their PDG photoexcitation helicity amplitudes,
allowed us to find the branching ratios , which have significantly
better accuracy than the PDG data. The total Breit-Wigner width of the
is model-dependent, we have obtained and using dispersion relations and the isobar model,
respectively. The results for the , ,
, are model dependent, only the signs and orders
of magnitude of their contributions to multipole amplitudes are determined. The
results for the are strongly model-dependent.Comment: 26 pages, 6 figure
Cognitive enhancing effects of voluntary exercise, caloric restriction and environmental enrichment: A role for adult hippocampal neurogenesis and pattern separation?
Several behavioural interventions, such as physical exercise, dietary restriction, and enriched environments are associated with both improved cognition and increased adult hippocampal neurogenesis. Whether the learning and memory improvements associated with these interventions are causally dependent on the upregulated neurogenesis has not yet been conclusively determined. However, with the accumulating evidence of a role for adult-born hippocampal neurons in spatial pattern separation, it is possible that the improvements in learning and memory result, at least in part, from an improvement in pattern separation. The following review focuses on three major behavioural manipulations associated with cognitive enhancement: voluntary exercise, caloric restriction, and environmental enrichment (including learning), and how increased neurogenesis may contribute to the enhancement by improving pattern separation.The authors would like to acknowledge financial contribution from the following funding sources: the Innovative Medicine Initiative Joint Undertaking under grant agreement no. 115008, of which resources are composed of a European Federation of Pharmaceutical Industries and Associations in-kind contribution and financial contribution from the European Union's Seventh Framework Programme (FP7/2007–2013); The Wellcome Trust/Medical Research Council (089703/Z/09/Z) and the Biotechnology and Biological Sciences Research Council (grant BB/G019002/1). C.A.O. received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 603016. B.A.K. was supported by Gates Cambridge.This is the author accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S235215461500087X
Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis
Masses, widths and photocouplings of baryon resonances are determined in a
coupled-channel partial wave analysis of a large variety of data. The
Bonn-Gatchina partial wave formalism is extended to include a decomposition of
t- and u-exchange amplitudes into individual partial waves. The multipole
transition amplitudes for and are
given and compared to results from other analyses.Comment: 18 pages, 14 figure
Heavy Flavour Physics at HERA - a Survey
At the HERA collider at DESY, high energy electron and positron beams
interact with proton beams. A review is presented of the variety of ways in
which these collisions produce final states containing charm and beauty quarks.Comment: 45 pages including 30 figures. Submitted to International Journal of
Modern Physics
Sparticle masses in deflected mirage mediation
We discuss the sparticle mass patterns that can be realized in deflected
mirage mediation scenario of supersymmetry breaking, in which the moduli,
anomaly, and gauge mediations all contribute to the MSSM soft parameters.
Analytic expression of low energy soft parameters and also the sfermion mass
sum rules are derived, which can be used to interpret the experimentally
measured sparticle masses within the framework of the most general mixed
moduli-gauge-anomaly mediation. Phenomenological aspects of some specific
examples are also discussed.Comment: 43 pages, 17 figures, references adde
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