2,089 research outputs found
Updates of PDFs in the MSTW framework
I present results on updates on PDFs which are obtained within the general
framework which led to the MSTW2008 PDF sets. There are some theory and
procedural improvements and a variety of new data sets, including many relevant
up-to-date LHC data. A new set of PDFs is very close to being finalised, with
no significant changes expected to the preliminary PDFs shown here.Comment: 6 pages, 6 figures,Published in PoS DIS (2014
Instantons and Chern-Simons flows in 6, 7 and 8 dimensions
The existence of K-instantons on a cylinder M^7 = R_tau x K/H over a
homogeneous nearly K"ahler 6-manifold K/H requires a conformally parallel or a
cocalibrated G_2-structure on M^7. The generalized anti-self-duality on M^7
implies a Chern-Simons flow on K/H which runs between instantons on the coset.
For K-equivariant connections, the torsionful Yang-Mills equation reduces to a
particular quartic dynamics for a Newtonian particle on C. When the torsion
corresponds to one of the G_2-structures, this dynamics follows from a gradient
or hamiltonian flow equation, respectively. We present the analytic (kink-type)
solutions and plot numerical non-BPS solutions for general torsion values
interpolating between the instantonic ones.Comment: 1+8 pages, 14 figures; talk presented at SQS-11 during 18-23 July,
2011, at JINR, Dubna, Russia; v2: missing * in eq.(1) adde
Acoustic characterization of crack damage evolution in sandstone deformed under conventional and true triaxial loading
We thank the Associate Editor, Michelle Cooke, and the reviewers, Ze'ev Reches and Yves Guéguen, for useful comments which helped to improve the manuscript. We thank J.G. Van Munster for providing access to the true triaxial apparatus at KSEPL and for technical support during the experimental program. We thank R. Pricci for assistance with technical drawings of the apparatus. This work was partly funded by NERC award NE/N002938/1 and by a NERC Doctoral Studentship, which we gratefully acknowledge. Supporting data are included in a supporting information file; any additional data may be obtained from J.B. (e-mail: [email protected]).Peer reviewedPublisher PD
Quay voices in Glasgow museums : an oral history of Glasgow dock workers
Notes on oral history project commissioned by Glasgow museums about Glasgow dock workers
reaction at high energies
We evaluate differential distributions for the four-body reaction at high energies which constitutes an irreducible background to
three-body processes , where , ,
, , . We consider central diffractive
contribution mediated by Pomeron and Reggeon exchanges as well as completely
new mechanism of emission of kaons from the proton lines. We include absorption
effects due to proton-proton interaction and kaon-kaon rescattering. We compare
our results with measured cross sections for the CERN ISR experiment. We make
predictions for future experiments at RHIC, Tevatron and LHC. Differential
distributions in invariant two-kaon mass, kaon rapidities and transverse
momenta of kaons are presented. Two-dimensional distribution in is particularly interesting. The higher the incident energy, the
higher preference for the same-hemisphere emission of kaons. We find that the
kaons from the new mechanism of emission directly from proton lines are
produced rather forward and backward but the corresponding cross section is
rather small. The processes considered here constitute a sizeable contribution
to the total proton-proton cross section as well as to kaon inclusive cross
section.
We consider a measurement of exclusive production of scalar meson
in the proton-proton collisions via decay. The
corresponding amplitude for exclusive central diffractive meson
production is calculated within the -factorization approach. The
influence of kinematical cuts on the signal-to-background ratio is discussed.Comment: 20 pages, 16 figures. text has been corrected and supplemented, cross
section for forward/backward mechanisms has been corrected. arXiv admin note:
substantial text overlap with arXiv:1103.564
Measurement of exclusive production of scalar meson in proton-(anti)proton collisions via decay
We consider a measurement of exclusive production of scalar
meson in the proton-proton collisions at LHC and RHIC and in
the proton-antiproton collisions at the Tevatron via decay. The corresponding amplitude for exclusive
double-diffractive meson production was obtained within the
-factorization approach including virtualities of active gluons and the
corresponding cross section is calculated with unintegrated gluon distribution
functions (UGDFs) known from the literature. The four-body reaction constitutes an irreducible background to the exclusive
meson production. We calculate several differential distributions
for process including absorptive
corrections. The influence of kinematical cuts on the signal-to-background
ratio is investigated. Corresponding experimental consequences are discussed.Comment: 16 pages, 10 figures, 2 table
Hyperbolic calorons, monopoles, and instantons
We construct families of SO(3)-symmetric charge 1 instantons and calorons on
the space H^3 x R. We show how the calorons include instantons and hyperbolic
monopoles as limiting cases. We show how Euclidean calorons are the flat space
limit of this family.Comment: 11 pages, no figures 1 reference added Published version available
at: http://www.springerlink.com/content/k0j4815u54303450
Charm and beauty quark masses in the MMHT2014 global PDF analysis
We investigate the variation in the MMHT2014 PDFs when we allow the heavy-quark masses mcmc and mbmb to vary away from their default values. We make PDF sets available in steps of Δmc=0.05 GeVΔmc=0.05 GeV and Δmb=0.25 GeVΔmb=0.25 GeV , and present the variation in the PDFs and in the predictions. We examine the comparison to the HERA data on charm and beauty structure functions and note that in each case the heavy-quark data, and the inclusive data, have a slight preference for lower masses than our default values. We provide PDF sets with three and four active quark flavours, as well as the standard value of five flavours. We use the pole mass definition of the quark masses, as in the default MMHT2014 analysis, but briefly comment on the MS¯¯¯¯¯¯¯MS¯ definition
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