1,058 research outputs found
Sequestering in models of F-term uplifting
We discuss the nature of sequestering supersymmetry breaking sectors in a
certain class of moduli stabilization in supergravity/string models, where a
negative vacuum energy of the nonperturbative moduli potential is canceled by
dynamically generated F-terms. Two illustrating examples are shown to sketch
the issues around the supersymmetry breaking, flavors and sequestering within
such a framework.Comment: 6 pages, no figure; Talks given at PASCOS08 (the 14th International
Symposium on Particles, Strings and Cosmology, Waterloo, Canada, June 2-6,
2008) and SUSY08 (the 16th International Conference on Supersymmetry and the
Unification of Fundamental Interactions, Seoul, Korea, June 16-21, 2008
Problems of Double Charm Production in Annihilation at GeV
Using the nonrelativistic QCD(NRQCD) factorization formalism, we calculate
the color-singlet cross sections for exclusive production processes
~ and ~~
at the center-of-mass energy =10.6 GeV. The cross sections are
estimated to be 5.5fb, 6.7fb, 1.1fb, and 1.6fb for and , respectively. The calculated
production rate is smaller than the recent Belle data by about an order of
magnitude, which might indicate the failure of perturbative QCD calculation to
explain the double-charmonium production data. The complete
color-singlet cross section for is calculated. In addition, we also evaluate the ratio
of exclusive to inclusive production cross sections. The ratio of
production to production could be consistent
with the experimental data.Comment: 10 pages, 4 figures. A few references added, errors and typoes
correcte
Electroproduction of psi' and polarized gluon distribution in a proton
In order to get information about the polarized gluon distribution in a
proton, we studied the electroproduction of \psi' in polarized electron and
polarized proton collisions in the framework of the NRQCD factorization
approach. The value of the cross section d\Delta\sigma / dp_T^2 for color-octet
mechanism is about 5 times larger than that for color-singlet one, and it might
be another test of the color-octet model if the polarized gluon distribution
\Delta g(x) is well known. Furthermore, we found that this reaction is quite
effective for testing the model of gluon polarization by measuring the double
spin asymmetry A_{LL} for the initial electron and proton. Though the shape of
p_T^2 distribution of A_{LL} is quite similar for the production mechanism with
color-octet and color-singlet, we can see a big difference in A_{LL} among
various models of the polarized gluon distribution function \Delta g(x).Comment: 9 pages, 6 figure
Direct dark matter search with the full data set of XMASS-I
XMASS-I was unique experiment, as single phase, large volume liquid xenon detector observation was
carried out during Nov. 20, 2013 to Feb. 1, 2019. Including WIMP dark matter searches, many rare event
search results by using XMASS-I data were reported so far, such as dark photon, axion, axion-like particle,
double electron capture.
After the end of the long stable data acquisition, analysis for WIMP dark matter searches with full data
set was processed. The analysis with total accumulated live time of 1590.9 days for the normal threshold
trigger(> 1 keVee) and 768.8 days for the low threshold trigger (>0.5keVee) with 832kg of liquid xenon
have been done.
Two search analyses were done with almost 5 years long stable data set. One is the fiducial volume
analysis in which nuclear recoil signal was searched in the detectorâs fiducial volume, which contained
97kg of liquid xenon. The other is the annual modulation analysis which signal was searched on all target
volumes of 832kg. In addition to nuclear recoil signal, signal from bremsstrahlung effect and Migdal effect
were also searched in the modulation analysis.
In the present circumstance for the dark matter searches, search by various methods is becoming more
important than ever. The results from XMASS-I full data set are unique and very valuable results
B Decays at BABAR
We present branching fraction and CP asymmetry results for a variety of B
decays based on up to 56.4 fb^-1 collected by the BaBar experiment running near
the Upsilon(4S) resonance at the PEP-II e+e- B-factory.Comment: 10 pages, 6 figures, presented at QCD02: High Energy Physics
International Conference in Quantum Chromodynamics, Montpellier, France, 2-9
Jul 200
J/psi Inclusive Production in ep Deep-Inelastic Scattering at DESY HERA
We calculate the cross section of J/psi plus jet associated production in ep
deep-inelastic scattering within the factorization formalism of nonrelativistic
quantum chromodynamics. Our analytic results disagree with previous analyses,
both for the colour-singlet and colour-octet channels. Our theoretical
predictions agree reasonably well with recent data taken by the H1
Collaboration at DESY HERA, significantly better than those obtained within the
colour-singlet model.Comment: 27 pages (Latex), 9 figures (Postscript), to appear in Nucl. Phys.
Quarkonium Photoproduction at Next-to-leading Order
We present the calculation of O(as^2 aem) corrections to heavy-quarkonium
total photoproduction cross-sections. Results are given for the colour-octet
component of S and P waves. The calculation is performed using covariant
projectors in dimensional regularization. A phenomenological study of the
results, including a discussion of the high-energy behaviour of the cross
sections, is presented. For gamma-p energies up to few hundred GeV the NLO
corrections significantly reduce the scale dependence of the production rates
relative to the Born-level results. Large small-x corrections arise at higher
energies, making the predictions strongly dependent on the shape of the gluon
density and on the choice of factorization scale.Comment: 32 pages, Latex, epsfig, 13 figure
Color-Octet Contributions to J/psi Photoproduction via Fragmentation at HERA
We study J/psi photoproduction via fragmentation at next-to-leading order in
the QCD-improved parton model, using the nonrelativistic factorization
formalism proposed by Bodwin, Braaten, and Lepage. We consider direct and
resolved photoproduction of prompt J/psi mesons and chi_{cJ} mesons radiatively
decaying to J/psi+gamma, taking into account the formation of both
color-singlet and color-octet c anti-c states. Adopting the values of the
long-distance color-octet matrix elements extracted from fits to prompt-J/psi
data recently taken at the Fermilab Tevatron, we predict that measurements of
J/psi photoproduction at DESY HERA should show a distinctive excess over the
expectation based on the color-singlet model at small values of the
inelasticity variable z. This is complementary to the expected enhancement at z
close to 1 due to the color-octet contribution to photon-gluon fusion.Comment: 10 pages (Latex), 3 figures (Postscript
J/psi Production: Tevatron and Fixed-Target Collisions
In this talk I show the results of a fit of the NRQCD matrix elements to the
CDF data for direct production, by including the radiative corrections
to the colour-singlet channel and the effect of the -smearing. Furthermore
I perform the NLO NRQCD analysis of production in fixed-target
proton-nucleon collisions and I fit the colour-octet matrix elements to the
available experimental data. The results are compared to the Tevatron ones.Comment: 6 pages, 3 figures. Talk given at the QCD99 Euroconference,
Montpellier, France, July 199
Charmonium Hybrid Production in Exclusive B Meson Decays
Recent data on charmonium production in B-meson decays suggest that
charmonium hybrid mesons with mass ~4 GeV may be produced in B-decay via
c\bar{c} colour octet operators. Some of these states are likely to be narrow
with clean signatures to J/\psi pi^+ pi^- final states. Experimental signatures
and search strategies for existing B-factories are described.Comment: references added and some of the text rewritten so it is cleare
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