LHC Symposium 2003: Summary Talk

This summary talk reviews the LHC 2003 Symposium, focusing on expectations as we prepare to leap over the current energy frontier into new territory. We may learn from what happened in the two most recent examples of leaping into new energy territory. Quite different scenarios appeared in those two cases. In addition, we review the status of the machine and experiments as reported at the Symposium. Finally, I suggest an attitude which may be most appropriate as we look forward to the opportunities anticipated for the first data from the LHC.Comment: Summary Talk: LHC Symposium, May 1-3, 2003, Fermilab, Batavia, IL US

Review of Heavy-Quark Production at Fixed-Target Experiments

An increasingly large amount of quality fixed-target data on heavy-quark production at fixed-target energies is appearing. This data can provide information across a range of physics topics. The topics vary from investigations of QCD predictions to the understanding of the structure of hadrons. Recent results on neutrino, photon, and hadron production of charm and beauty will be reviewed in this context. The greatest insight will come from combining multiple measurements as they relate to the physics topics, and by ensuring that the parameters used in models are consistent with all the measurements. We have not yet really entered the time when this has been done for fixed-target measurements

Photoemission spectroscopy and sum rules in dilute electron-phonon systems

A family of exact sum rules for the one-polaron spectral function in the low-density limit is derived. An algorithm to calculate energy moments of arbitrary order of the spectral function is presented. Explicit expressions are given for the first two moments of a model with general electron-phonon interaction, and for the first four moments of the Holstein polaron. The sum rules are linked to experiments on momentum-resolved photoemission spectroscopy. The bare electronic dispersion and the electron-phonon coupling constant can be extracted from the first and second moments of spectrum. The sum rules could serve as constraints in analytical and numerical studies of electron-phonon models.Comment: 4 page

Reformulation of the Stochastic Potential Switching Algorithm and a Generalized Fourtuin-Kasteleyn Representation

A new formulation of the stochastic potential switching algorithm is presented. This reformulation naturally leads us to a generalized Fourtuin-Kasteleyn representation of the partition function Z. A formula for internal energy E and that of heat capacity C are derived from derivatives of the partition function. We also derive a formula for the exchange probability in the replica exchange Monte Carlo method. By combining the formulae with the Stochastic Cutoff method, we can greatly reduce the computational time to perform internal energy and heat capacity measurements and the replica exchange Monte Carlo method in long-range interacting systems. Numerical simulations in three dimensional magnetic dipolar systems show the validity and efficiency of the method.Comment: 11 pages, 6 figures, to appear in PR

Developments in Rare Kaon Decay Physics

We review the current status of the field of rare kaon decays. The study of rare kaon decays has played a key role in the development of the standard model, and the field continues to have significant impact. The two areas of greatest import are the search for physics beyond the standard model and the determination of fundamental standard-model parameters. Due to the exquisite sensitivity of rare kaon decay experiments, searches for new physics can probe very high mass scales. Studies of the k->pnn modes in particular, where the first event has recently been seen, will permit tests of the standard-model picture of quark mixing and CP violation.Comment: One major revision to the text is the branching ratio of KL->ppg, based on a new result from KTeV. Several references were updated, with minor modifications to the text. A total of 48 pages, with 28 figures, in LaTeX; to be published in the Annual Review of Nuclear and Particle Science, Vol. 50, December 200

Comment on ``Spin Dependent Hopping and Colossal Negative Magnetoresistance in Epitaxial Nd0.52Sr0.48MnO3Nd_{0.52}Sr_{0.48}MnO_{3} Films in Fields up to 50 T''

Recently Wagner et al. [Phys. Rev. Lett. Vol. 81, P. 3980 (1998)] proposed that Mott's original model be modified to incorporate a hopping barrier which depends on the misorientation between the spins of electrons at the initial and the final states in an elementary process. They further claimed that using the model they can explain the observed scaling behavior-- negative-magnetoresistivity scaling proportional to the Brillouin function $\cal{B}$ in the ferromagnetic state and to ${\cal{B}}^2$ in the paramagnetic state. In this comment we argue that the modification needed for Mott's original model is different from that proposed by Wagner et al. and further show that our picture will successfully explain the observed scaling in the two regimes.Comment: 1 pag

Polaron Transport in the Paramagnetic Phase of Electron-Doped Manganites

The electrical resistivity, Hall coefficient, and thermopower as functions of temperature are reported for lightly electron-doped Ca(1-x)La(x)MnO(3)(0 <= x <= 0.10). Unlike the case of hole-doped ferromagnetic manganites, the magnitude and temperature dependence of the Hall mobility for these compounds is found to be inconsistent with small-polaron theory. The transport data are better described by the Feynman polaron theory and imply intermediate coupling (alpha \~ 5.4) with a band effective mass, m*~4.3 m_0, and a polaron mass, m_p ~ 10 m_0.Comment: 7 pp., 7 Fig.s, to be published, PR