124489366
Energy moments for quark jets at PETRA
Measurements of energy moments for single quark jets at c.m. energies between 12 and 31.6 GeV are presented. The data, corrected for detector effects and initial state radiation, are compared to QCD predictions in the leading log approximation. Non perturbative effects are found to be moderate, and they strongly decrease with increasing c.m. energy. Once partly corrected for the presence of these fragmentation effects, our data agree well with all features of the leading log prediction, and in particular with the variation of the strong coupling constant over a wide range of energies and momentum transfers.
104230837
tau mass measurement from e mu, e pi and (mu pi, mu mu, pi pi) channels at BES/BEPC
125773108
A Measurement of J / psi decay widths
126182293
Evidence of psi(3770) nonD anti-D decay to J / psi pi+ pi-
121138073
BESII detector simulation
A Monte Carlo program based on GEANT3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.
122313186
Search For Neutral Higgs Bosons From Supersymmetry In Z-decays
The light scalar Higgs boson h and the pseudoscalar Higgs boson A of the minimal supersymmetric standard model have been searched for in the processes e+e−→hff and e+e−→hA using data collected by ALEPH at the LEP e+e− collider, with center of mass energies at and near the Z peak. Using a variety of signatures adapted to various mass ranges for h and A, we have excluded a large domain in the parameter space. For large values of ν2ν1, the ratio of the vacuum expectation values of the two Higgs fields, the whole range from 0 to 38.8 GeV is excluded for Mh and MA at 95% CL.
123010822
Failure of perturbative scaling in SU(3) lattice gauge theory
Abstract The Asymptotic Freedom (AF) prediction for the energy density of the pure SU(3) Yang-Mills theory in a constant abelian chromomagnetic field is clearly seen to be inconsistent with a lattice calculation. This failure of AF fully confirms previous results obtained for SU(2), both analytically and by lattice methods. In view of this important confirmation, we conclude that the generally accepted picture of QCD can not be maintained in its present form.
119074539
Further study of the possible scaling region of lattice chiral fermions
In the possible scaling region for an SU(2) lattice chiral fermion advocated in Nucl. Phys. B486, 282 (1997), no hard spontaneous symmetry breaking occurs and doublers are gauge-invariantly decoupled via mixing with composite three-fermion states that are formed by local multifermion interactions. However, the strong coupling expansion breaks down due to the no ``static limit'' for the low-energy limit $(pa\ensuremath{\sim}0).$ In both neutral and charged channels, we further analyze the relevant truncated Green functions of three-fermion operators by strong coupling expansion and analytical continuation of these Green functions in momentum space. It is shown that in the low-energy limit these relevant truncated Green functions of three-fermion states with the ``wrong'' chiralities positively vanish due to the generalized form factors (the wave-function renormalizations) of these composite three-fermion states vanishing as $O[{(\mathrm{pa})}^{4}]$ for $\mathrm{pa}\ensuremath{\sim}0.$ This strongly implies that the composite three-fermion states with the ``wrong'' chirality are ``decoupled'' in this limit and the low-energy spectrum is chiral; as a consequence, chiral gauge symmetries can be exactly preserved.
17990668
Lattice formulation of the standard model
Abstract Combining the Kaplan surface mode approach for chiral fermions with added terms motivated by Eichten and Preskill suggests the possibility for a lattice regularization of the standard model which is finite, exactly gauge invariant, and only has physically desired states in its low energy spectrum. The conjectured scheme manifestly requires anomaly cancelation and explicitly contains baryon and lepton number violating terms.
15236936
On A Possible Ground State for Quantum Gravity (
A variational calculation is presented of the ADM-energy of the quantized gravitational field around a wormhole solution of the classical Einstein’s equations. One finds the energy of such state to be in general lower than the perturbative ground state, in which the quantized gravity field fluctuates around flat (Euclidean) space-time. As a result the strong indication emerges that a gas (or a lattice) of wormholes of Planck mass and average distance lp, the Planck length, may be a good approximation of the Ground State of Quantum Gravity, some implications of which are reviewed.
18226349
Aspects of Dynamical Symmetry Breaking on a Lattice
In the context of four-fermion and gauge interactions, the Schwinger-Dyson equation for the fermion self-energy function is studied with the Wilson fermion on a lattice. We find that the critical line obtained by Bardeen, Leung and Love is modified. No additional Goldstone bosons appear in the spectrum of fundamental particles. Massive solutions to the Schwinger-Dyson equation turn out to be possible for a small gauge coupling.