792 research outputs found
Summary of Spin Physics Parallel Sessions
We summarize the activities in the spin physics parallel sessions of the
conference on intersections between particle and nuclear physics.Comment: Latex, 5 pages, to appear in the Proceedings of the 8th Conference on
Intersections between Particle and Nuclear Physics (CIPANP 2003
Spin dependent fragmentation function at Belle
The measurement of the so far unknown chiral-odd quark transverse spin
distribution in either semi-inclusive DIS (SIDIS) or inclusive measurements in
pp collisions at RHIC has an additional chiral-odd fragmentation function
appearing in the cross section. These chiral-odd fragmentation functions (FF)
can for example be the so-called Collins FF or the Interference FF. HERMES has
given a first hint that these FFs are nonzero, however in order to measure the
transversity one needs these FFs to be precisely known. We have used 29.0
fb of data collected by the Belle experiment at the KEKB
collider to measure azimuthal asymmetries for different charge combinations of
pion pairs and thus access the Collins FF.Comment: Results presented at the DIS 2006 conference in Tsukuba, Japa
Spin dependent fragmentation functions at Belle
The Belle detector at the KEKB e+e− collider provides large
amounts of statistics to study the fragmentation of light quarks into final state hadrons. In addition to unpolarized fragmentation functions also spin dependent fragmentation can be studied. Belle has successfully extracted asymmetries related to the Collins and interference fagmentation functions for charged pions
Sivers effect in Drell Yan at RHIC
On the basis of a fit to the Sivers effect in deep-inelastic scattering, we
make predictions for single-spin asymmetries in the Drell-Yan process at RHIC.Comment: 10 pages, 7 figures, 1 table. v2: References and comments added,
minor correction
Three loop anomalous dimension of the second moment of the transversity operator in the MSbar and RI' schemes
We compute the anomalous dimension of the second moment of the transversity
operator, \bar{\psi} \sigma^{\mu\nu} D^\rho \psi, at three loops in both the
MSbar and RI' schemes. As a check on the result we also determine the O(1/N_f)
critical exponent of the n-th moment of the transversity operator in
d-dimensions in the large N_f expansion and determine leading order information
on the n dependence of the anomalous dimension at three and four loops in
MSbar. In addition the RI' anomalous dimension of the non-singlet twist-2
operator, \bar{\psi} \gamma^\mu D^\nu \psi, is also determined.Comment: 18 latex pages; additional reference include
Test of CPT and Lorentz invariance from muonium spectroscopy
Following a suggestion of Kostelecky et al. we have evaluated a test of CPT
and Lorentz invariance from the microwave spectroscopy of muonium. Hamiltonian
terms beyond the standard model violating CPT and Lorentz invariance would
contribute frequency shifts and to
and , the two transitions involving muon spin flip, which were
precisely measured in ground state muonium in a strong magnetic field of 1.7 T.
The shifts would be indicated by anti-correlated oscillations in and
at the earth's sidereal frequency. No time dependence was found in
or at the level of 20 Hz, limiting the size of some CPT
and Lorentz violating parameters at the level of GeV,
representing Planck scale sensitivity and an order of magnitude improvement in
sensitivity over previous limits for the muon.Comment: 4 pages, 4 figures, uses REVTeX and epsf, submitted to Phys. Rev.
Let
A Hadron Blind Detector for the PHENIX Experiment
A novel Hadron Blind Detector (HBD) has been developed for an upgrade of the
PHENIX experiment at RHIC. The HBD will allow a precise measurement of
electron-positron pairs from the decay of the light vector mesons and the
low-mass pair continuum in heavy-ion collisions. The detector consists of a 50
cm long radiator filled with pure CF4 and directly coupled in a windowless
configuration to a triple Gas Electron Multiplier (GEM) detector with a CsI
photocathode evaporated on the top face of the first GEM foil.Comment: 4 pages, 3 figures, Quark Matter 2005 conference proceeding
The Spin Structure of the Proton and Polarized Collider Physics
We summarise the present status of the proton spin problem and the physics
possibilities for future polarized ep and pp colliders. This summary is based
on the presentations and discussion sessions at the workshop ``The Spin
Structure of the Proton and Polarized Collider Physics'' (Trento, July 23-28,
2001).Comment: 27 pages, 22 figure
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