Review of Final LEP Results or A Tribute to LEP

After a comment on the performance of LEP some highlights of the LEP1 and LEP2 physics programmes are reviewed. The talk concentrates on the precision measurements at the Z resonance, two fermion production above the Z, W+W- production, ZZ production, indirect limits on the Higgs mass, LEP contributions to the exploration of the CKM matrix, and on the LEP measurements of alpha_s.Comment: Proceedings of the XX International Symposium on Lepton and Photon Interactions at High Energies Rome, Italy, July 200

Remarks Concerning the Study of Four-Jet Events from Hadronic Decays of the Z0

The angular correlations of four-jet events from hadronic decays of the Z0 have been studied in the past mainly to extract from them the fundamental constants of quantum chromodynamics called colour factors. Previous studies have used all the available phase-space in order to maximize statistics. In this note we want to point out the possibility that significant differences between experiment and theory in restricted regions of phase-space might have escaped detection. Such differences could be a harbinger of the existence of new particles. Some preliminary results are presented.Comment: 9 pages, 3 figure

New NLO Parametrizations of the Parton Distributions in Real Photons

We present new NLO sets of parton distributions in real photons based on a scheme invariant definition of the non-perturbative input. We compare the theoretical predictions with LEP data and a best fit allows us to constrain the parameters of the distributions. The shape of the gluon distribution is poorly constrained and we consider the possibility to measure it in photoproduction experiments. Three parametrizations which aim to take into account the scattering of LEP data are proposed. They are compared to other NLO parametrizations.Comment: 38 pages, 23 Postscript figures, fig. 6,7,8,9 improved, comparisons with other NLO parametrizations, added reference

A new gamma*-p / pbar-p factorization test in diffraction, valid below Q^2 about 6 GeV^2

One of the key experimental issues in high energy hadron physics is the extent to which data from the diffractive interaction mechanism may be described by a factorized formula which is the product of a universal term describing the probability of finding a Pomeron in a proton (loosely referred to as the "Pomeron flux-factor") and a term decribing the Pomeron's interaction with the other incident proton. In the present paper, after demonstrating that existing data on diffractive gamma*-p and pbar-p interactions show that the Pomeron flux-factor is not universal, we present the results of a new test of factorization in these interactions which does not rely on universality of the flux-factor. The test is satisfied to within ~20% for 1 < Q^2 ~ 6 GeV^2 and beta < 0.2 in the gamma*-p interactions, suggesting that the resons for non-universality of the flux-factor have a limited effect on the factorization itself. However, a clear breakdown of this test is observed at larger Q^2. Kharzeev and Levin suggest that this can be attributed to the onset of QCD evolution effects in the Pomeron's structure. The breakdown occurs in a Q^2 region which agrees with their estimates of a small Pomeron size.Comment: 20 pages, 7 Encapsulated Postscript figures, LaTex, submitted to European Phisical Journal

B Physics at the Z0 Resonance

B physics results from e+ e- annihilation at the Z0 resonance are reviewed. A vast program is summarised, including the study of B+, B0d, B0s and b baryon lifetimes, the time dependence of B0d and B0s oscillations, the width difference in the B0s system, and the measurements of the magnitudes of the CKM matrix elements Vcb and Vub.Comment: 17 pages, 8 figures, presented at the UK Phenomenology Workshop on Heavy Flavour and CP Violation, 17-22 September 200

The neutrino velocity anomaly as an explanation of the missing observation of neutrinos in coincidence with GRB

The search for neutrinos emitted in coincidence with Gamma-Bay Burst has been so far unsuccessfully. In this paper we show that the recent result reported by the OPERA Collaboration on an early arrival time of muon neutrinos with respect to the one computed assuming the speed of light in vacuum could explain the null search for neutrinos in coincidence with Gamma-Ray Burst

Recent Low x and Diffractive Collider Data

Selected recent data from collider experiments pertaining to the understanding of QCD at low Bjorken-x are reviewed. The status of QCD and Regge factorisation in hard diffractive interactions is discussed in terms of data from HERA and the Tevatron. The possibility of anomalous behaviour in the $\gamma \gamma$ total cross section is confronted with the most recent measurements from LEP. Data from all three colliders that are sensitive to possible BFKL effects are presented and different interpretations are discussed.Comment: 9 pages, introductory talk from the 1999 Durham Phenomenology Workshop on Collider Physic

On the physics and technology of gaseous particle detectors

Despite an already long and fruitful history, gaseous elementary-particle detectors remain today an important mainstay of high-energy and nuclear physics experiments and of radiation detection in general. In here we briefly describe some of the gaseous detector's main technologies and applications, along with some unsolved gas-discharge physics aspects of practical relevance.Comment: Submitted to Plasma Sources in Science and Technolog

Constraining the Unitarity Triangle with B -> V gamma

We discuss the exclusive radiative decays $B\to K^{*}\gamma$, $B \to\rho\gamma$, and $B\to\omega\gamma$ in QCD factorization within the Standard Model. The analysis is based on the heavy-quark limit of QCD. Our results for these decays are complete to next-to-leading order in QCD and to leading order in the heavy-quark limit. Special emphasis is placed on constraining the CKM-unitarity triangle from these observables. We propose a theoretically clean method to determine CKM parameters from the ratio of the $B\to\rho l\nu$ decay spectrum to the branching fraction of $B\to\rho\gamma$. The method is based on the cancellation of soft hadronic form factors in the large energy limit, which occurs in a suitable region of phase space. The ratio of the $B\to\rho\gamma$ and $B\to K^{*}\gamma$ branching fractions determines the side $R_{t}$ of the standard unitarity triangle with reduced hadronic uncertainties. The recent Babar bound on $B(B^0\to\rho^0\gamma)$ implies $R_t < 0.81 (\xi/1.3)$, with the limiting uncertainty coming only from the SU(3) breaking form factor ratio $\xi$. This constraint is already getting competitive with the constraint from $B_{s}$-$\bar B_{s}$ mixing. Phenomenological implications from isospin-breaking effects are briefly discussed.Comment: 23 pages, 8 figure