3,066,785 research outputs found
Search for Physics beyond the Standard Model at the Tevatron
Recent searches for physics beyond the standard model at the Tevatron are
reported, with emphasis on supersymmetry.Comment: to appear in Proceedings of SUSY06, the 14th International Conference
on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine,
California, 12-17 June 200
IRSF/SIRIUS JHKs near-infrared variable star survey in the Magellanic Clouds
We carried out a NIR variable star survey toward the Large and Small
Magellanic Clouds using the InfraRed Survey Facility (IRSF) at Sutherland,
South African Astronomical Observatory. This survey project was initiated in
Dember 2000, and since then, we kept monitoring a total area of 3 square
degrees along the LMC bar and also an area of 1 square degree around the center
of the SMC, sufficiently large to do statistical analysis and to make complete
catalog of variable red giants in the Magellanic Clouds. The detection limits
(S/N=10) of the survey are 17.0, 16.5 and 15.5 at J, H and Ks, respectively. In
this article, we present some results on infrared variables that are not
detected by the previous optical surveys. We show that they do not fall on the
standard period-Ks magnitude relation for Mira-type variables pulsating in the
fundamental mode.Comment: 3 pages, 2 figures. To appear in "Stellar Pulsation: Challenges for
Theory and Observation", Eds. J. Guzik and P. Bradle
Heavy Flavor Production at PHENIX at RHIC
A study of heavy flavor production in different collision systems in various
kinematic regions presents an opportunity to probe cold nuclear medium and hot
dense matter effects. Results from the PHENIX experiment on and open
charm production in Au+Au and Cu+Cu collisions at =200 GeV are
presented. The data show strong suppression in central AA collisions,
similar to NA50 results, and strong suppression in high open charm
production. The production in Au+Au and d+Au collisions is compared to
understand the cold nuclear medium effects. The data show significant cold
nuclear effects in charm production in d+Au collisions at forward and backward
rapidity ranges.Comment: 4 pages, 3figures, CIPANP2006, May 29-June 3, 2006. San Juan,
PuertoRic
Hadron Blind Detector for the PHENIX Experiment at RHIC
The PHENIX collaboration has designed a conceptually new Hadron Blind
Detector (HBD) for electron identification in high density hadron environment.
The HBD will identify low momentum electron-positron pairs to reduce the
combinatorial background in the mass region below 1 GeV/c^2. The HBD shall be
installed in PHENIX during the 2007 physics run. The HBD is a windowless
proximity focusing Cherenkov detector with a radiator length of 50 cm, CsI
photocathode and three layers of Gas Electron Multipliers (GEM) for gas
amplification. Pure CF_4 serves both as a radiator and as a detector gas. The
radiation budget of the device is less than 3% of a radiation length.Comment: 4 page
Using the Balance Function to study the charge correlations of hadrons
We present the recent Balance Function (BF) results obtained by the NA49
collaboration for the pseudo-rapidity dependence of non-identified charged
particle correlations for two SPS energies. Experimental results indicate a
clear centrality dependence only in the mid-rapidity region. The results of an
energy dependence study of the BF throughout the whole SPS energy range will
also be discussed. In addition, the correlation of identified hadrons is
studied and presented for the first time. The study of hadron correlation has
also been extended in order to cope with the high multiplicity environment that
is expected to be seen at LHC. We will present the latest results from
simulations concerning the extension of these studies to the ALICE experiment.Comment: To appear in the proccedings of the "Quark Confinement and Hadron
Spectrum VII" conferenc
High Rapidity Physics with the BRAHMS Experiment
We report the study of the nuclear modification factor R_{AuAu} as function
of pT and pseudo-rapidity in Au+Au collisions at top RHIC energy. We find this
quantity almost independent of pseudo-rapidity. We use the pbar/pi- ratio as a
probe of the parton density and the degree of thermalization of the medium
formed by the collision. The pbar/pi- ratio has a clear rapidity dependence.
The combination of these two measurements suggests that the pseudo-rapidity
dependence of the R_{AuAu results from the competing effects of energy loss in
a dense and opaque medium and the modifications of the wave function of the
high energy beams in the initial state.Comment: 5 pages, four figures, to appear in the proceedings of the 9th
Conference on the Intersections of Particle and Nuclear Physics (CIPANP
2006), Puerto Rico, 30 May - 3 June 200
Double Longitudinal Spin Asymmetry in Neutral Pion Production in Polarized p+p Collisions at sqrt(s)=200 GeV at PHENIX
A major goal of the RHIC spin program is to measure \Delta g, the gluon
contribution to the proton's spin. Measurements by PHENIX of the double
longitudinal spin asymmetry, A_LL, of the neutral pion production at
mid-rapidity in polarized proton collisions have been shown to constrain \Delta
g. Results from the 2005 RHIC run, as well as high p_T data from the 2006 RHIC
run, are presented. The results disfavor maximal positive and negative values
of \Delta g. A measurement of azimuthally independent double transverse spin
asymmetry, A_TT, is also presented.Comment: 4 pages, 2 figures, to be published in the Proceedings of the 17th
International Spin Physics Symposium (SPIN2006), Kyoto (Japan), October 2-7,
200
Prospects for SUSY searches in CMS and ATLAS
We discuss how the CMS and ATLAS experiments are preparing for the analysis
of first LHC data with emphasis on the search for supersymmetry. We will show
the importance of the understanding of detector, trigger, reconstruction and
backgrounds, and we will present realistic estimates of the reach of CMS and
ATLAS.Comment: 9 pages, 12 figures. Contribution to the proceedings of the 16th
international conference on supersymmetry and the unification of fundamental
interactions, SUSY08, Seoul, Korea, June 16-21, 200
Precision Calibration of the D0 HCAL in Run II
Most of the physics analyses at a hadron collider rely on a precise
measurement of the energy of jets in the final state. This requires a precise
in situ calibration of the calorimeter with the final detector setup. We
present the basic procedure and results of the in situ gain calibration of the
D0 HCAL in Run II. The gain calibration works on top of the pulser-based
calibration of the readout electronics and is based entirely on collision data.Comment: 8 pages, 5 figures, presented at XII International Conference on
Calorimetry in High-Energy Physic
Study of the Flux and Spectral Variations in the VHE Emission from the Blazar Markarian 501, with the MAGIC Telescope
The blazar Markarian 501 (Mrk 501) was observed above 100 GeV with the MAGIC
Telescope during May, June and July 2005. The high sensitivity of the
instrument made possible the detection of the source with high significance in
each of the observing nights. During this observational campaign, the emitted
gamma-ray flux from Mkn 501 was found to vary by one order of magnitude, and
showed a high correlation with spectral changes. Intra-night flux variability
was also observed, with flux-doubling times of ~2 minutes. The data showed a
clear evidence of a spectral peak (in the nuFnu representation) during the
nights when the gamma-ray activity was highest. The location of this spectral
feature was found to be correlated with the emitted gamma-ray flux. In these
proceedings we discuss some of the results of this unprecedented spectral and
temporal analysis of Mrk 501 observations in the very high energy range.Comment: 4 pages, 3 figures, manuscript submitted on behalf of the MAGIC
collaboration to the First GLAST Symposium (oral presentation
- …
