4,801 research outputs found
Collinear factorization violation and effective field theory
The factorization of amplitudes into hard, soft and collinear parts is known
to be violated in situations where incoming particles are collinear to outgoing
ones. This result was first derived by studying limits where non-collinear
particles become collinear. We show that through an effective field theory
framework with Glauber operators, these factorization-violating effects can be
reproduced from an amplitude that is factorized before the splitting occurs. We
confirm results at one-loop, through single Glauber exchange, and at two-loops,
through double Glauber exchange. To approach the calculation, we begin by
reviewing the importance of Glauber scaling for factorization. We show that for
any situation where initial state and final state particles are not collinear,
the Glauber contribution is entirely contained in the soft contribution. The
contributions coming from Glauber operators are necessarily non-analytic
functions of external momentum, with the non-analyticity arising from the
rapidity regulator. The non-analyticity is critical so that Glauber operators
can both preserve factorization when it holds and produce
factorization-violating effects when they are present.Comment: 55 Pages, 5 figure
Clinical study on the optic nerve protection of calcium dobesilate in treating glaucoma
AIM:To observe the protective effect of calcium dobesilate on optic nerve of glaucoma patients whose intraocular pressure has been under control through operation.<p>METHODS: A total of 78 inpatients(89 eyes)with glaucoma in this hospital from January, 2011 to February, 2012 were enrolled. All patients were randomly divided into treatment group and control group with 6 months in a course. The visual acuity, visual field(mean sensibility, MS), and intraocular pressure were measured at the experiment onset and 6 months later to evaluate the clinical effect.<p>RESULTS: There were no statistically significant differences in the visual acuity, intraocular pressure between the two groups neither at the experiment onset nor after 6 months(<i>P</i>>0.05). The mean sensibility(MS)of the treatment group was obviously improved(14.56±5.03 <i>vs </i>18.9±5.77, <i>P</i><0.05)with statistically significant differences before and after the treatment, while the MS remained unchanged in the control group(14.75±5.17 <i>vs </i>13.48±4.69). There are statistically significant difference between the treatment group and the control group. Compared to the ratio of improvement, stability, and deterioration in the control group(10.3%, 48.7%, 41.0%), the indexes were changed obviously in the treatment group(64.1%, 28.2%, 7.7%,<i>P</i><0.05)with statistically significant difference between the two groups.<p>CONCLUSION:Calcium dobesilate can improve mean retinal sensitivity and protect the optic nerve in glaucoma patients whose intraocular pressure has been controlled
Signature of Pseudo Nambu-Goldstone Higgs boson in its Decay
If the Higgs boson is a pseudo Nambu-Goldstone boson (PNGB), the
contact interaction induced by the invariants of the
non-linear sigma model is free from its nonlinearity effects. The process
can be used to eliminate the universal effects of heavy
particles, which can fake the nonlinearity effects of the PNGB Higgs boson in
the process (,\ ). We demonstrate that the
ratio of the signal strength of and
is good to distinguish the signature of the PNGB Higgs boson from Higgs
coupling deviations
Rare decay in a CP spontaneously broken two Higgs doublet model
The Higgs boson mass spectrum and couplings of neutral Higgs bosons to
fermions are worked out i n a CP spontaneously broken two Higgs doublet model
in the large tan case.
The differential branching ratio, forward-backward asymmetry, CP asymmetry
and lepton polarization for are computed. It is shown that
effects of neutral Higgs bosons are quite significant when is
large. Especially, the CP violating normal polarization can be as large
as several percents.Comment: 27 pages, text updated, new numerical results include
Scales, Couplings Revisited and Low Energy Phenomenology in M-theory on
We revisit the eleven dimension Planck scale, the physical scale of the
eleventh dimension, the physical scale of Calabi-Yau manifold and coupling in
hidden sector in M-theory on . And we discuss the reasonable bound on
them. Considering F-term of dilaton and moduli SUSY breaking and choosing two
repersentative points which correspond to scalar quasi-massless scenario and
dilaton dominant SUSY breaking scenario respectively, we analyze experimental
constraints to the parameter space. The sparticle spectrum and some
phenomenological predictions are also given.Comment: 35 pages and 8 eps files. One error on fig1b is correcte
Bottom Baryons
Recently CDF and D0 collaborations observed several bottom baryons. In this
work we perform a systematic study of the masses of bottom baryons up to
in the framework of heavy quark effective field theory (HQET) using the
QCD sum rule approach. The extracted chromo-magnetic splitting between the
bottom baryon heavy doublet agrees well with the experimental data.Comment: 8 pages, 5 figures, 3 tables. More discussions and references adde
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