194 research outputs found
Enhanced charm hadroproduction due to nonlinear corrections to the DGLAP equations
We have studied the effects of nonlinear scale evolution of the parton
distribution functions to charm production in collisions at center-of-mass
energies of 5.5, 8.8 and 14 TeV. We find that the differential charm cross
section can be enhanced up to a factor of 4-5 at low . The enhancement is
quite sensitive to the charm quark mass and the renormalization/factorization
scales.Comment: 4 pages, 3 eps-figures. To appear in the proceedings of the
seventeenth international conference on Ultra-Relativistic Nucleus-Nucleus
Collisions (Quark Matter 2004
Isomeric states close to doubly magic Sn studied with JYFLTRAP
The double Penning trap mass spectrometer JYFLTRAP has been employed to
measure masses and excitation energies for isomers in Cd,
Cd, Cd and Te, for isomers in In and
In, and for isomers in Sn and Sb. These first
direct mass measurements of the Cd and In isomers reveal deviations to the
excitation energies based on results from beta-decay experiments and yield new
information on neutron- and proton-hole states close to Sn. A new
excitation energy of 144(4) keV has been determined for Cd. A good
agreement with the precisely known excitation energies of Cd,
Sn, and Sb has been found.Comment: 10 pages, 6 figures, submitted to Phys. Rev.
Mass measurements in the vicinity of the doubly-magic waiting point 56Ni
Masses of 56,57Fe, 53Co^m, 53,56Co, 55,56,57Ni, 57,58Cu, and 59,60Zn have
been determined with the JYFLTRAP Penning trap mass spectrometer at IGISOL with
a precision of dm/m \le 3 x 10^{-8}. The QEC values for 53Co, 55Ni, 56Ni, 57Cu,
58Cu, and 59Zn have been measured directly with a typical precision of better
than 0.7 keV and Coulomb displacement energies have been determined. The Q
values for proton captures on 55Co, 56Ni, 58Cu, and 59Cu have been measured
directly. The precision of the proton-capture Q value for 56Ni(p,gamma)57Cu,
Q(p,gamma) = 689.69(51) keV, crucial for astrophysical rp-process calculations,
has been improved by a factor of 37. The excitation energy of the proton
emitting spin-gap isomer 53Co^m has been measured precisely, Ex = 3174.3(10)
keV, and a Coulomb energy difference of 133.9(10) keV for the 19/2- state has
been obtained. Except for 53Co, the mass values have been adjusted within a
network of 17 frequency ratio measurements between 13 nuclides which allowed
also a determination of the reference masses 55Co, 58Ni, and 59Cu.Comment: 14 pages, 13 figures, submitted to Phys. Rev.
DGLAP analyses of nPDF: constraints from data
We explain how the constraints from present experimental data can be used to
obtain the nPDF in the framework of LO DGLAP evolution. We will also compare
the only two available sets of this type and comment on the important
information that neutrino factories could provide.Comment: 1 pages, 1 postscript figure. Invited talk at the NuFact'02 workshop
(Neutrino Factories based on Muon Storage Rings), London, July 200
Q_EC values of the Superallowed beta-Emitters 10-C, 34-Ar, 38-Ca and 46-V
The Q_EC values of the superallowed beta+ emitters 10-C, 34-Ar, 38-Ca and
46-V have been measured with a Penning-trap mass spectrometer to be 3648.12(8),
6061.83(8), 6612.12(7) and 7052.44(10) keV, respectively. All four values are
substantially improved in precision over previous results.Comment: 9 pages, 7 figures, 5 table
Hard probes in heavy ion collisions at the LHC: PDFs, shadowing and collisions
This manuscript is the outcome of the subgroup ``PDFs, shadowing and
collisions'' from the CERN workshop ``Hard Probes in Heavy Ion Collisions at
the LHC''. In addition to the experimental parameters for collisions at
the LHC, the issues discussed are factorization in nuclear collisions, nuclear
parton distributions (nPDFs), hard probes as the benchmark tests of
factorization in collisions at the LHC, and semi-hard probes as
observables with potentially large nuclear effects. Also, novel QCD phenomena
in collisions at the LHC are considered. The importance of the
program at the LHC is emphasized.Comment: The writeup of the working group "PDFs, shadowing and
collisions" for the CERN Yellow Report on Hard Probes in Heavy Ion Collisions
at the LHC, 121 pages. Subgroup convenors: K.J. Eskola, J.w. Qiu (theory) and
W. Geist (experiment). Editor: K.J. Eskol
Q-values of the Superallowed beta-Emitters 26m-Al, 42-Sc and 46-V and their impact on V_ud and the Unitarity of the CKM Matrix
The beta-decay Q_EC-values of the superallowed beta emitters 26m-Al, 42-Sc
and 46-V have been measured with a Penning trap to a relative precision of
better than 8x10^-9. Our result for 46-V, 7052.72(31) keV, confirms a recent
measurement that differed significantly from the previously accepted
reaction-based Q_EC-value. However, our results for 26m-Al and 42-Sc,
4232.83(13) keV and 6426.13(21) keV, are consistent with previous
reaction-based values. By eliminating the possibility of a systematic
difference between the two techniques, this result demonstrates that no
significant shift in the deduced value of V_ud should be anticipated.Comment: 4 pages, 2 figures, 1 table. Submitted to Phys. Rev. Let
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