8040521
Mass Differences within Isotopic Multiplets in a SUSY Electro-weak Theory
Based on the idea that electromagnetism is responsible for the mass differences within isotopic multiplets, and possibly also for the whole mass of the electron, a supersymmetric gauge theoretical model based on the group $SU(2)_{L} \times SU(2)_{R} \times U(1)_{Y}$ is constructed. Under some reasonable assumptions to the SUSY particle spectrum, a correct sign for the mass difference within an isotopic multiplet is obtained. This might provide a possible scenario to understand the old puzzle of the proton-neutron mass difference.
121797308
Simultaneous multiplicity and forward energy characterization of particle spectra in Au + Au collisions at 11.6-A-GeV/c
In this paper Au+Au collisions at 11.6A GeV/c are characterized by two global observables: the energy measured near zero degrees (E{sub ZCAL}) and the total event multiplicity. Particle spectra are measured for different event classes that are defined in a two-dimensional grid of both global observables. For moderately central events ({sigma}/{sigma}{sub int}{lt}12{percent}) the proton dN/dy distributions do not depend on E{sub ZCAL} but only on the event multiplicity. In contrast the shape of the proton transverse spectra shows little dependence on the event multiplicity. The change in the proton dN/dy distributions suggests that different conditions are formed in the collision for different event classes. These event classes are studied for signals of new physics by measuring pion and kaon spectra and yields. In the event classes doubly selected on E{sub ZCAL} and multiplicity there is no indication of any unusual pion or kaon yields, spectra, or K/{pi} ratio even in the events with extreme multiplicity. {copyright} {ital 1999} {ital The American Physical Society}
34566683
Sign of the neutron-proton mass difference in an SU(2) x U(1) supersymmetric toy model: A possible scenario for solving the old puzzle.
Based on the idea that electromagnetism is responsible for mass differences within isotopic multiplets (e.g., pointlike neutron and proton or {ital u} and {ital d} quarks), we generalize an SU(2){times}U(1) model in a toy field theory of vectors to a supersymmetric model and investigate the finite mass difference within the isotopic doublet. It is found that under soft-supersymmetry breaking, a positive {ital n}-{ital p} mass difference can be obtained under reasonable assumptions for the parameters involved.
10335512
Antilambda production in Au+Au collisions at 11.7A GeV/c.
We present results for antilambda and antiproton production in Au+Au collisions at 11.7 A GeV/c including spectra and extracted invariant yields for both species in central and peripheral collisions in the rapidity range 1.0<y<1.4. The antilambda yield increases from dN(Lambda;)/dy = 1.2(+0.7+0.2)(-0.6-0.2)x10(-3) in peripheral collisions to 19(+4+3)(-5-2)x10(-3) in central collisions. The direct antiproton yield is deduced from the measured total antiproton spectra to extract the ratio of antilambda-to-direct-antiproton production. The Lambda/p ratio near midrapidity increases from 0.26(+0.19+0.5)(-0.15-0.4) in peripheral collisions to 3.6(+4.7+2.7)(-1.8-1.1) in central collisions, a value larger than current theoretical estimates.
18889238
Studies of the vector meson mass generation scheme by chiral anomalies in two-dimensional nonAbelian gauge theories
Higher order effects of the two-dimensional non-Abelian gauge theories, in which the vector-meson mass is generated by chiral anomalies, will be studied. The $\beta$ function and the topological nature of the non-linear $\sigma$ model in the action and unitarity of the theory will be discussed.
30310361
Purely gluonic soliton solutions in the leading-logarithm model.
Finite-energy, purely gluonic, soliton solutions are considered in atwo-dimensional space on the basis of the leading-logarithm model which isequivalent to electromagnetism with a dielectric constant /epsilon/logarithmically proportional to the fields. Solutions, in the absence ofsources, are possible provided /epsilon//gt/0 and /epsilon//lt/0 are bothpresent in the same space.
209835401
Search for events with large missing transverse momentum, jets, and at least two tau leptons in 7 TeV proton–proton collision data with the ATLAS detector
A search for events with large missing transverse momentum, jets, and at least two tau leptons has been performed using 2 fb(-1) of proton-proton collision data at root s = 7 TeV recorded with the ...
116994417
Measurement of $\eta^\prime\rightarrow \pi^+\pi^- e^+e^-$ and $\eta^\prime\rightarrow \pi^+\pi^-\mu^+\mu^-$
Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be \BR(\eta' to pi+pi-e+e-) = (2.11\pm0.12 (stat.)\pm0.15 (syst.))\times10^{-3}, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No \eta' signal is found in the pi+ pi- mu+ mu- mass spectrum, and the upper limit is determined to be \BR(\eta' to pi+ pi- mu+ mu-)<2.9\times10^{-5} at the 90% confidence level.
53482318
A preliminary lattice design of a tau-charm factory storage ring in Beijing
A preliminary lattice design of a tau-charm factory (/spl tau/cF) storage ring is described. This storage ring is suggested to be built to the east of the injector, BEL, of BEPC. In addition, some considerations on improving the design will be outlined.
60626146
ILC Reference Design Report: ILC Global Design Effort and World Wide Study
120285402
ON THE ENERGY AND MASS DEPENDENCE OF THE MULTIPLICITY IN RELATIVISTIC HEAVY-ION INTERACTIONS
The average multiplicities of singly charged relativistic particles in oxygen-induced interactions with a nuclear emulsion target are studied over the energy range 2.1–200 A GeV. A similar energy dependence as for proton-induced interactions is observed. Both the number of participating nucleons and the number of binary collisions are shown to be of importance for the particle production.