12,531 research outputs found
Experimental Search for Pentaquarks
The experimental evidence for pentaquarks, both old an new, is discussed.
Constraints due to scattering data from previous decades is first
reviewed, followed by experiments with positive evidence and those with null
results. Finally, the problem of the narrow width of the Theta+ pentaquark is
discussed, along with theoretical implications.Comment: Review article for Progress in Particle and Nuclear Physics (34
pages
Evidence for the Strangeness S=+1 Pentaquark from LEPS and CLAS Experiments
There are now several experimental collaborations that have seen evidence for
a narrow state in the mass spectrum of the () system. Two of these
experiments, from the LEPS collaboration in Japan and the CLAS collaboration in
the USA, are described briefly. Both use similar photoproduction reactions with
a pair in the final state. In addition, data from the CLAS
collaboration for the reaction are presented for the
first time, which has no prominant peak in the () mass spectrum when the
angle is limited to forward angles.Comment: Hadron 2003 Conference Proceedings (5 pages
A Method to Unambiguously Determine the Parity of the Theta+ Pentaquark
With the recent discovery of the pentaquark, the question of
its parity is paramount since this will constrain the correct description of
its internal structure. We show that the measurement of the spin singlet and
triplet cross sections for the reaction
will unambiguously determine the parity of the .Comment: 3 page
Search for Pentaquarks at BABAR
The results of searches for the strange pentaquark states, Theta(1540)+,
Xi(1860)-- and Xi(1860)0 in data recorded by the BABAR experiment are
presented. We search for these three states inclusively in 123.4 fb^-1 of e+ e-
annihilation data produced at the PEP-II asymmetric storage rings; we find no
evidence for their production in any physics process, and set limits on their
production rates that are well below the measured rates for conventional
baryons. We also search for Theta(1540)+ produced in interactions of electrons
or hadrons in the material of the inner part of the detector. No evidence for
this state is found in a sample with much higher statistics than similar
electroproduction experiments that claim a signal.Comment: 4 pages, 4 postscript figues, contributed to the Proceedings of QCD
05, Montpellie
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