3,382 research outputs found
W production at large transverse momentum at the Large Hadron Collider
We study the production of W bosons at large transverse momentum in pp
collisions at the Large Hadron Collider (LHC). We calculate the complete
next-to-leading order (NLO) corrections to the differential cross section. We
find that the NLO corrections provide a large increase to the cross section
but, surprisingly, do not reduce the scale dependence relative to leading order
(LO). We also calculate next-to-next-to-leading-order (NNLO) soft-gluon
corrections and find that, although they are small, they significantly reduce
the scale dependence thus providing a more stable theoretical prediction.Comment: 12 pages, 7 figure
Randomized Extended Kaczmarz for Solving Least-Squares
We present a randomized iterative algorithm that exponentially converges in
expectation to the minimum Euclidean norm least squares solution of a given
linear system of equations. The expected number of arithmetic operations
required to obtain an estimate of given accuracy is proportional to the square
condition number of the system multiplied by the number of non-zeros entries of
the input matrix. The proposed algorithm is an extension of the randomized
Kaczmarz method that was analyzed by Strohmer and Vershynin.Comment: 19 Pages, 5 figures; code is available at
https://github.com/zouzias/RE
The one-dimensional Keller-Segel model with fractional diffusion of cells
We investigate the one-dimensional Keller-Segel model where the diffusion is
replaced by a non-local operator, namely the fractional diffusion with exponent
. We prove some features related to the classical
two-dimensional Keller-Segel system: blow-up may or may not occur depending on
the initial data. More precisely a singularity appears in finite time when
and the initial configuration of cells is sufficiently concentrated.
On the opposite, global existence holds true for if the initial
density is small enough in the sense of the norm.Comment: 12 page
Lack of self-averaging of the specific heat in the three-dimensional random-field Ising model
We apply the recently developed critical minimum energy subspace scheme for
the investigation of the random-field Ising model. We point out that this
method is well suited for the study of this model. The density of states is
obtained via the Wang-Landau and broad histogram methods in a unified
implementation by employing the N-fold version of the Wang-Landau scheme. The
random-fields are obtained from a bimodal distribution (), and the
scaling of the specific heat maxima is studied on cubic lattices with sizes
ranging from to . Observing the finite-size scaling behavior of the
maxima of the specific heats we examine the question of saturation of the
specific heat. The lack of self-averaging of this quantity is fully illustrated
and it is shown that this property may be related to the question mentioned
above.Comment: 8 pages, 7 figures, extended version with two new figures, version as
accepted for publication to Physical Review
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