5,560 research outputs found
What Does the CMS Measurement of W-polarization Tell Us about the Underlying Theory of the Coupling of W-Bosons to Matter?
We discuss results of the CMS collaboration on the sensitivity of the LHC to
boson polarisation in the process using the variable directly connected to
angle of the outgoing lepton in the rest frame of the decaying . We have
shown that for a given , interference between different polarizations of
the -boson is not negligible, and needs to be taken into account when
considering the differential cross-section with respect to . The
variable suggested by CMS collaboration is highly suitable variable to study
LHC sensitivity to couplings of -boson to fermions. We note that
the experimental sensitivity to W-boson polarization which is much higher than
that to () parameter space can be turned around and used to identify
deviations from the Standard Model as a signal for new physics at the LHC.Comment: 11 pages, 8 figures. Updated to match the final version published in
JHEP with updated figures and polished tex
The Effect of a Rapidity Gap Veto on the Discrete BFKL Pomeron
We investigate the sensitivity of the discrete BFKL spectrum, which appears
in the gluon Green function when the running coupling is considered, to a lower
cut-off in the relative rapidities of the emitted particles. We find that the
eigenvalues associated to each of the discrete eigenfunctions decrease with the
size of the rapidity veto. The effect is stronger on the lowest eigenfunctions.
The net result is a reduction of the growth with energy for the Green function
together with a suppression in the regions with small transverse momentum.Comment: 10 pages, 3 figure
Gluon Contributions to Parity-Violating Asymmetries in Polarized Proton-Proton Scattering
We report on a calculation of one-loop weak corrections to polarized
quark-gluon scattering and the corresponding crossed channels. Such
contributions are suppressed formally by one power of alpha_s relative to W- or
Z-mediated quark-quark scattering, but would enable the spin asymmetry of the
gluon distribution to contribute to parity-violating asymmetries that will soon
be investigated in polarized proton-proton scattering experiments at RHIC. In
certain kinematic regions, gluon contributions to parity-violating asymmetries
can be as large as 10% of the tree-level W- and Z-exchanges in quark-quark
scattering, but usually only where the parity-violating asymmetries are already
small.Comment: LATEX 12 pages, 6 figure
The Green Function for the BFKL Pomeron and the Transition to DGLAP Evolution
We consider the (process-independent) Green function for the BFKL equation in
the next-to-leading order approximation, with running coupling, and explain
how, within the semi-classical approximation, it is related to Green function
of the Airy equation. The unique Green function is obtained from a combination
of its required ultraviolet behaviour compatible with asymptotic freedom and an
infrared limit phase imposed by the non-perturbative sector of QCD. We show
that at sufficiently large gluon transverse momenta the corresponding gluon
density matches that of the DGLAP analysis, whereas for relatively small values
of the gluon transverse momentum the gluon distribution is sensitive to the
Regge poles, whose positions are determined both by the non-pertubative QCD
dynamics and physics at large transverse momenta.Comment: 14 pages, 2 figure
Evolution and Devolution of Knowledge: A Tale of Two Biologies
Anthropological inquiry suggests that all societies classify animals and plants in similar ways. Paradoxically, in the same cultures that have seen large advances in biological science, citizenry's practical knowledge of nature has dramatically diminished. Here we describe historical, cross-cultural and developmental research on how people ordinarily conceptualize organic nature (folkbiology), concentrating on cognitive consequences associated with knowledge devolution. We show that results on psychological studies of categorization and reasoning from âstandard populationsâ fail to generalize to humanity at large. Usual populations (Euro-American college students) have impoverished experience with nature, which yields misleading results about knowledge acquisition and the ontogenetic relationship between folkbiology and folkpsychology. We also show that groups living in the same habitat can manifest strikingly distinct behaviors, cognitions and social relations relative to it. This has novel implications for environmental decision making and management, including commons problems.
Radiative Corrections to Chargino Production with Polarized Beams
We show that radiative corrections to chargino production in
electron-positron annihilation with polarized beams can be large especially in
the case of right handed electrons. In addition, there is some dependency on
the squark masses that allows us to extract information about the squark
spectrum from the chargino production.Comment: 4 pages, including 4 figures. Talk given at Linear Collider Workshop
2000--LCWS, Fermilab, Chicago, October 24-28, 200
Radiatively Corrected Chargino Pair Production at LEP2
One-loop radiative corrections to the production cross section of a pair of
light charginos in e+e- colliders are calculated within the MSSM. Top and
bottom quarks and squarks are considered in the loops, and they are
renormalized using the MS-bar scheme. If the center of mass energy is equal to
192 GeV, positive corrections typically of 10% to 15% are found when the squark
mass parameters are equal to 1 TeV.Comment: 6 pages, including 5 figures. Latex. Talk given by M.A.D. at the
International Workshop "Beyond the Standard Model: From Theory to
Experiment", 13--17 October 1997, Valencia, Spai
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