36,519 research outputs found
Factorization and resummation for transverse thrust
We analyze transverse thrust in the framework of Soft Collinear Effective
Theory and obtain a factorized expression for the cross section that permits
resummation of terms enhanced in the dijet limit to arbitrary accuracy. The
factorization theorem for this hadron-collider event-shape variable involves
collinear emissions at different virtualities and suffers from a collinear
anomaly. We compute all its ingredients at the one-loop order, and show that
the two-loop input for next-to-next-to-leading logarithmic accuracy can be
extracted numerically, from existing fixed-order codes.Comment: 47 pages, 12 figures. v2: journal versio
Addendum: Electroweak Sudakov effects in W, Z and gamma production at large transverse momentum
In this addendum to Phys. Rev. D 88, no. 1, 013009 (2013), we give results
for the electroweak Sudakov corrections in gauge-boson production at large
transverse momentum p_T at proton colliders. In order for the results to be
easily usable, we provide a simple and accurate parameterization of the
corrections as a function of p_T and the center-of-mass energy \sqrt{s}.
Additionally, we also discuss the dependence of the electroweak corrections on
the rapidity of the produced boson, and comment on the complications that arise
in the photon-production case due to isolation requirementsComment: 4 pages, 4 figure
Electroweak Sudakov effects in W, Z and gamma production at large transverse momentum
We study electroweak Sudakov effects in single W, Z and gamma production at
large transverse momentum using Soft Collinear Effective Theory. We present a
factorized form of the cross section near the partonic threshold with both QCD
and electroweak effects included and compute the electroweak corrections
arising at different scales. We analyze their size relative to the QCD
corrections as well as the impact of strong-electroweak mixing terms. Numerical
results for the vector-boson cross sections at the Large Hadron Collider are
presented.Comment: 14 pages, 5 figures. v2: Minor changes, references added. Journal
versio
Quantum gas mixtures in different correlation regimes
We present a many-body description for two-component ultracold bosonic gases
when one of the species is in the weakly interacting regime and the other is
either weakly or strongly interacting. In the one-dimensional limit the latter
case system is a hybrid in which a Tonks-Girardeau gas is immersed in a
Bose-Einstein condensate, which is an example of a new class of quantum system
involving a tunable, superfluid environment. We describe the process of phase
separation microscopically and semiclassically in both situations and show that
the quantum correlations are maintained in the separated phase.Comment: 4 pages, 3 figure
A halo-independent lower bound on the dark matter capture rate in the Sun from a direct detection signal
We show that a positive signal in a dark matter (DM) direct detection
experiment can be used to place a lower bound on the DM capture rate in the
Sun, independent of the DM halo. For a given particle physics model and DM mass
we obtain a lower bound on the capture rate independent of the local DM
density, velocity distribution, galactic escape velocity, as well as the
scattering cross section. We illustrate this lower bound on the capture rate by
assuming that upcoming direct detection experiments will soon obtain a
significant signal. When comparing the lower bound on the capture rate with
limits on the high-energy neutrino flux from the Sun from neutrino telescopes,
we can place upper limits on the branching fraction of DM annihilation channels
leading to neutrinos. With current data from IceCube and Super-Kamiokande
non-trivial limits can be obtained for spin-dependent interactions and direct
annihilations into neutrinos. In some cases also annihilations into
or start getting constrained. For spin-independent interactions
current constraints are weak, but they may become interesting for data from
future neutrino telescopes.Comment: 27 pages, 8 figures. Added discussion on equilibrium. Added section
5.4 on form factor uncertainties. Updated figures with SK new limits.
Published in JCA
Astrophysics independent bounds on the annual modulation of dark matter signals
We show how constraints on the time integrated event rate from a given dark
matter (DM) direct detection experiment can be used to set a stringent
constraint on the amplitude of the annual modulation signal in another
experiment. The method requires only very mild assumptions about the properties
of the local DM distribution: that it is temporally stable on the scale of
months and spatially homogeneous on the ecliptic. We apply the method to the
annual modulation signal in DAMA/LIBRA, which we compare to the bounds derived
from the constraints on the time-averaged rates from XENON10, XENON100, CDMS
and SIMPLE. Assuming a DM mass of 10 GeV, we show that a DM interpretation of
the DAMA/LIBRA signal is excluded at 6.3sigma (4.6sigma) for isospin conserving
(violating) spin-independent interactions, and at 4.9sigma for spin-dependent
interactions on protons.Comment: 4 pages, 4 figure
Fused Azulenes: Possible Organic Multiferroics
We present compelling theoretical results showing that fused azulene
molecules are strong candidates for exhibiting room temperature multiferroic
behavior, i.e., having both, ferroelectric and ferromagnetic properties. If
this is experimentally proved, these systems will be the first organic
multiferroic materials with important potential applications.Comment: 4 pages, 4 figure
Next-to-next-to-leading logarithmic resummation for transverse thrust
We obtain a prediction for the hadron-collider event-shape variable
transverse thrust in which the terms enhanced in the dijet limit are resummed
to next-to-next-to-leading logarithmic accuracy. Our method exploits
universality properties made manifest in the factorized expression for the
cross section and only requires one-loop calculations. The necessary two-loop
ingredients are extracted using known results and existing numerical codes. Our
technique is general and applicable to other observables as well.Comment: 6 pages, 2 figures. v2: Corrected values in Eq.(15); updated Figure 2
accordingl
Ionization of ions
Charged particle binary encounter model modified for evaluating ionization cross section of positive ions by electron impac
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