7,585 research outputs found
Reply to ``Comment on `Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions' ''
We demonstrate that in the process of deducing the constraint on the
electroweak mixing angle in our paper, we have indeed been working
with three mass scales while implementing (331) model.Comment: Revtex, 3pages, Reply to hep-ph/9902448, Submitted to Phys. Rev.
Towards a first estimate of the gluon Sivers function from data in collisions at RHIC
Within a generalized parton model approach, with inclusion of spin and
intrinsic transverse momentum effects, we show how the latest, highly precise,
midrapidity data on the transverse single spin asymmetry measured in
by the PHENIX Collaboration at RHIC [1], can be used to get a
first estimate on the still poorly known gluon Sivers distribution. To this end
we also adopt the present information on the quark Sivers functions, as
extracted from semi-inclusive deeply inelastic scattering data. This analysis
updates a previous study by some of us where a first bound on this distribution
was obtained [2].Comment: RevTex4, 10 pages, 7 eps figures. V2: discussion on the process
dependence of the quark Sivers function, with two new plots (Fig. 4), added
in Section II. One reference added. Results unchanged. Matches the published
versio
The Polarized and Unpolarized Photon Content of the Nucleon
The equivalent photon content of polarized and unpolarized nucleons (protons,
neutrons), utilized in Weizs\"acker--Williams approximations, are presented.
For this purpose a new expression for the elastic photon component of a
polarized nucleon is derived. The inelastic photon components are obtained from
the corresponding momentum evolution equations subject to the boundary
conditions of their vanishing at some low momentum scale. The resulting photon
asymmetries, important for estimating cross section asymmetries in photon
induced subprocesses are also presented for some typical relevant momentum
scales.Comment: LaTeX, 16 pages, 6 figure
Probing the transverse dynamics and polarization of gluons inside the proton at the LHC
Transverse momentum dependent gluon distributions encode fundamental information on the structure of the proton. Here we show how they can be accessed in heavy quarkonium production in proton-proton collisions at the LHC. In particular, their first determination could come from the study of an isolated J/? or ? particle, produced back to back with a photon
Delineating the polarized and unpolarized photon distributions of the nucleon in eN collisions
The production rates of lepton-photon and dimuon pairs at the HERA collider
and the HERMES experiment are evaluated in the leading order equivalent photon
approximation. It is shown that the production rates are sufficient to
facilitate the extraction of the polarized and unpolarized equivalent photon
distributions of the proton and neutron in the available kinematical regions.
It is pointed out that these results indicate the possibility of additional,
independent, tests concerning the unpolarized and polarized structure functions
F_{1,2}^N and g_{1,2}^N, respectively, of the nucleon.Comment: Final version, to appear in Eur. Phys.
Comment on ``Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions''
We point out that if the majoron-like scheme is implemented within a 331
model, there must exist at least three different mass scales for the scalar
vacuum expectation values in the model.Comment: 4 pages, no figures, Revtex. To be published in Physical Review
Probing the Perturbative NLO Parton Evolution in the Small- Region
A dedicated test of the perturbative QCD NLO parton evolution in the very
small- region is performed. We find a good agreement with recent precision
HERA-data for , as well as with the present determination of the
curvature of . Characteristically, perturbative QCD evolutions result in
a positive curvature which increases as decreases. Future precision
measurements in the very small -region, , could provide a
sensitive test of the range of validity of perturbative QCDComment: Revised version, to appear in EPJ
Dijet imbalance in hadronic collisions
The imbalance of dijets produced in hadronic collisions has been used to
extract the average transverse momentum of partons inside the hadrons. In this
paper we discuss new contributions to the dijet imbalance that could complicate
or even hamper this extraction. They are due to polarization of initial state
partons inside unpolarized hadrons that can arise in the presence of nonzero
parton transverse momentum. Transversely polarized quarks and linearly
polarized gluons produce specific azimuthal dependences of the two jets that in
principle are not suppressed. Their effects cannot be isolated just by looking
at the angular deviation from the back-to-back situation, rather they enter jet
broadening observables. In this way they directly affect the extraction of the
average transverse momentum of unpolarized partons that is thought to be
extracted. We discuss appropriately weighted cross sections to isolate the
additional contributions.Comment: 15 pages, 2 figures; revised version, published in Phys. Rev.
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