897 research outputs found
Limits on Low Scale Gravity from and
It has been proposed recently that the scale of quantum gravity (``the string
scale'') can be few TeV with extra dimensions of size mm so that, at distances greater than , Newtonian
gravity with GeV is reproduced if . Exchange of virtual gravitons in this theory generates
higher-dimensional operators involving SM fields, suppressed by powers of
. We discuss constraints on this scenario from the contribution of these
operators to the processes . We find
that LEP2 can place a limit TeV from .Comment: Replacing an earlier version. A discussion of using polarized
electron beams and some minor comments have been adde
Experimental Summary on Hadronic Decays: A TAU98 Review
Selected results on hadronic decays of the tau lepton from the TAU98 Workshop
are reviewed. A comprehensive picture emerges for strange particle branching
fractions, and exploration of resonant substructure of both strange and
non-strange decays is seen to have matured substantially.Comment: 10 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
The photon structure function measurements from LEP
The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers QED structure functions and the hadronic structure function F_2^gamma.The present knowledge of the structure of the photon based on measurements of photon structure functions is discussed. This review covers QED structure functions and the hadronic structure function F_2^gamma
Nucleus polarizability contribution to the hydrogen-deuterium isotope shift
The correction to the hydrogen-deuterium isotope shift due to the proton and
deuteron polarizability is evaluated on the basis of modern experimental data
on the structure functions of inelastic lepton-nucleus scattering. The
numerical value of this contribution is equal 63\pm 12 Hz.Comment: 5 page
The Transversity Function and Double Spin Azimuthal Asymmetry in Semi-Inclusive Pion Leptoproduction
We show that the transverse momentum dependent transversity function is
proportional to the longitudinal polarization of a quark in a transversely
polarized proton. This result suggests an alternative, convenient method for
determining transversity, without knowing unusual fragmentation functions. The
method consists of measuring the double spin azimuthal asymmetry in
semi-inclusive pion leptoproduction by a transversely polarized proton target.
The asymmetry, which is twist 3, is estimated to be more than 10% under the
most favorable conditions. The experiment we suggest is feasible at facilities
like DESY and CERN.Comment: extended version; to appear on Int. Jou. Mod. Phys.
Signatures of HyperCharge Axions in Colliders
If in addition to the standard model fields, a new pseudoscalar field that
couples to hypercharge topological number density, the hypercharge axion,
exists, it can be produced in colliders in association with photons or Z
bosons, and detected by looking for its decay into photons or Z's. For a range
of masses below a TeV and coupling above a fraction of 1/TeV, existing data
from LEP II and the Tevatron can already put interesting constraints, and in
future colliders accessible detection range is increased significantly. The
hypercharge axion can help in explaining the matter-antimatter asymmetry in the
universe.Comment: 11 pages, 8 figures, uses axodraw.st
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