Remarks upon the mass oscillation formulas

The standard formula for mass oscillations is often based upon the approximation $t \approx L$ and the hypotheses that neutrinos have been produced with a definite momentum $p$ or, alternatively, with definite energy $E$. This represents an inconsistent scenario and gives an unjustified reduction by a factor of two in the mass oscillation formulas. Such an ambiguity has been a matter of speculations and mistakes in discussing flavour oscillations. We present a series of results and show how the problem of the factor two in the oscillation length is not a consequence of gedanken experiments, i.e. oscillations in time. The common velocity scenario yields the maximum simplicity.Comment: 9 pages, AMS-Te

Light quark mass ratio from Dalitz plot of η→π+π−π0\eta \to \pi^+\pi^-\pi^0 decay

High statistics Dalitz-plot distribution of $\eta \to \pi^+\pi^-\pi^0$ decay obtained recently by KLOE collaboration \cite{kloe} is fitted to the results of corresponding theoretical calculations in Chiral Perturbation Theory (ChPT) with unitarity corrections taken into account. The quark mass ratio $Q = \sqrt{(m^2_s - (m_d + m_u)^2/4)/(m^2_d - m^2_u)}$ can be otained from this analysis. We get $Q= 22.8\pm 0.4$ which differs from the value $Q_{DT} = 24.2$ that follows from Dashen's theorem and agrees with recently calculated electromagnetic kaon mass difference.Comment: 2 pages, no figure

Selex

A summary of the path which lead to a high energy physics group at Instituto de Fisica de la Universidad Autonoma de San Luis Potosi is presented. This group is the result of the initial push made by Leon Lederman at the beginning of the 80's.Comment: Talk given at the Session honoring Leon Lederman at the VII Mexican Workshop on Particles and Fields, Merida, Mexico, November 10-17, 1999. Proceedings to be published by AI

First Results on Hadron Spectroscopy at COMPASS

The COMPASS fixed-target experiment at the CERN SPS is dedicated to the study of hadron structure and dynamics. One goal of the physics programme using hadron beams is the search for new states, in particular the search for $J^{PC}$ exotic states and glueballs. After a short pilot run in 2004 (190 GeV/c $\pi^{-}$ beam, lead target), we started our hadron spectroscopy programme in 2008 by collecting unprecedented statistics using 190 GeV/c negative hadron beams on a liquid hydrogen target. A similar amount of data with 190 GeV/c positive hadron beams has been taken in 2009, as well as some data (negative beam) on nuclear targets. As a first result the observation of a significant $J^{PC}$ spin-exotic signal in the 2004 data -- consistent with the disputed $\pi_1(1600)$ -- was recently published. Our spectrometer features good coverage by electromagnetic calorimetry, crucial for the detection of final states involving $\pi^0$, $\eta$ or $\eta'$, and the 2008/09 data provide an excellent opportunity for the simultaneous observation of new states in different decay modes. The diffractively produced $(3\pi)^{-}$ system for example can be studied in $\pi^{-}\pi^{+}\pi^{-}$ and $\pi^{-}\pi^{0}\pi^{0}$ final states, respectively. Observation of new states in both modes provides important consistency checks within the same experiment as the reconstruction of charged and neutral modes rely on completely different parts of the apparatus. We present the first results and give an overview of the status on various ongoing analyses of the 2008/09 data.Comment: 6 pages, 5 figures, to appear in the proceedings of the 35th Conference on High Energy Physics 2010, Paris, France, 22-28 Jul 201

First Observation of the Rare Decay Mode K-long -> e+ e-

In an experiment designed to search for and study very rare two-body decay modes of the K-long, we have observed four examples of the decay K-long -> e+ e-, where the expected background is 0.17+-0.10 events. This observation translates into a branching fraction of 8.7^{+5.7}_{-4.1} X 10^{-12}, consistent with recent theoretical predictions. This result represents by far the smallest branching fraction yet measured in particle physics.Comment: 9 pages, 3 figure

Minimum impact and immediacy of citations to physics open archives of arXiv.org: Science Citation Index based reports

The present work has calculated the minimum Open Archive Impact Factors and Open Archive Immediacy Index for the Physics Classes of arXiv.org as calculated for traditional journals in Journal Citation Reports of the Institute of Scientific Information using Science Citation Index without the citation by the classes itself. The calculated Impact Factors reveal that High-Energy Physics classes of arXiv.org (‘hep-th’, ‘hep-lat’, ‘hep-ex’, and ‘hep-ph’) have made more impact on the scientific community than any other classes except ‘nucl-ex’. The Impact Factors for the year 2003 are: ‘hep-th’ (0.999), ‘nucl-ex’ (0.806), ‘hep-lat’ (0.766), ‘hep-ex’ (0.73), ‘hep-ph’ (0.719), ‘nucl-th’ (0.338), ‘quant-ph’ (0.334), ‘cond-mat’ (0.313), ‘astro-ph’ (0.195), ‘math-ph’ (0.162), ‘physics’ (0.061), and ‘gr-qc’ (0.002). If the period for getting the citations to the open archive classes is considered one year as against two years for journal articles, the rank of the classes is the same. The immediacy of citing the Open Archives is also high for the High-Energy Physics classes. The Immediacy Indexes for the year 2003 are: ‘hep-ex’ (0.619), ‘hep-th’ (0.454), ‘hep-ph’ (0.44), ‘hep-lat’ (0.263), ‘nucl-ex’ (0.238), ‘quant-ph’ (0.202), ‘nucl-th’ (0.185), ‘cond-mat’ (0.168), ‘astro-ph’ (0.094), ‘math-ph’ (0.075), ‘physics’ (0.03), and ‘gr-qc’ (0.002). The impact is definitely much higher than what is concluded from the calculated factors because self-citations are not reckoned in the study. Use of web-tools like ‘Citebase’, ‘Citeseer’ etc. may strengthen the above argument

One pion events by atmospheric neutrinos: A three flavor analysis

We study the one-pion events produced via neutral current (NC) and charged current (CC) interactions by the atmospheric neutrinos. We analyze the ratios of these events in the framework of oscillations between three neutrino flavors. The ratios of the CC events induced by $\nu_e$ to that of the NC events and a similar ratio defined with $\nu_\mu$ help us in distinguishing the different regions of the neutrino parameter space.Comment: 14 pages, 4 figures (separate postscript files