Search For Production Of Invisible Final States In Single Photon Decays Of Upsilon1s PDF Download
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Total Pages | : 7 |
Release | : 2010 |
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Download Search for Production of Invisible Final States in Single-Photon Decays of Upsilon(1S). Book in PDF, ePub and Kindle
We search for single-photon decays of the?(1S) resonance,? →? + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A°, or a pair of dark matter particles,?{bar?}. Both A° and {chi} are assumed to have zero spin. We tag?(1S) decays with a dipion transition?(2S) →??−?(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m{sub A{sup o}} ≤ 9.2GeV and m{sub {chi}} ≤ 4.5GeV in the sample of 98 x 106?(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.
Author | : Lucas O. Winstrom |
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Total Pages | : 452 |
Release | : 2009 |
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Download Search for Invisible Decays of the Upsilon (1S) Meson at BABAR Book in PDF, ePub and Kindle
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Total Pages | : 17 |
Release | : 2008 |
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Download Search for Invisible Decays of a Light Scalar in Radiative Transitions Y(3S)-]gamma A0 Book in PDF, ePub and Kindle
We search for a light scalar particle produced in single-photon decays of the [Upsilon](3S) resonance through the process [Upsilon](3S) → [gamma] + A°, A° → invisible. Such an object appears in Next-to-Minimal Supersymmetric extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to b-quarks. If, in addition, there exists a light, stable neutralino, decays of A° could be preferentially to an invisible final state. We search for events with a single high-energy photon and a large missing mass, consistent with a 2-body decay of [Upsilon](3S). We find no evidence for such processes in a sample of 122 x 106 [Upsilon](3S) decays collected by the BABAR collaboration at the PEP-II B-factory, and set 90% C.L. upper limits on the branching fraction [Beta]([Upsilon](3S) → [gamma]A°) x [Beta](A° → invisible) at (0.7-31) x 10−6 in the mass range m{sub A{sup 0}} ≤ 7.8 GeV. The results are preliminary.
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Release | : 1986 |
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Download A Search for Narrow States in Radiative Upsilon Decays Book in PDF, ePub and Kindle
A search for new states produced in radiative UPSILON(1S) decays is accomplished by observing the inclusive photon energy spectrum. A narrow resonance in the energy spectrum indicates the existence of a new state X produced by the process UPSILON .-->. .gamma. X. The analysis is based on approximately 0.44 x 106 UPSILON(1S) events produced at the DORIS II ee− storage ring. These data were collected with the Crystal Ball detector between April 1983 and May 1986. This analysis finds no evidence for a new state, so upper limits on the branching ratio BR(UPSILON .-->. .gamma. X) are derived, assuming the state X decays primarily to high-multiplicity hadronic final states. In particular, if the state X were a minimal Higgs particle, its primary decay mode would be to the heaviest fermion-antifermion pair energetically available. For the radiative UPSILON(1S) decays studied here, the heavy fermions would be c anti c or s anti s quark states, over most of the relevant Higgs' mass range. The resulting upper limit for BR(UPSILON(1S) .-->. .gamma. X) is highly energy dependent but for X mass between 1.5 GeV and 8.0 GeV, the 90% confidence level upper limit is better than 8.0 x 10−4. For a Higgs' mass near 5.0 GeV, the upper limit is about 2.0 x 10−4 which is approximately equal to the lowest order calculation for the Wilczek mechanism. The Wilczek calculation with QCD radiative corrections predict branching ratios below the limits set here for all Higgs' masses.
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Total Pages | : 504 |
Release | : 1987 |
Genre | : Nuclear physics |
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Download High Energy Physics Index Book in PDF, ePub and Kindle
Author | : Georg G. Raffelt |
Publisher | : University of Chicago Press |
Total Pages | : 692 |
Release | : 1996-05 |
Genre | : Science |
ISBN | : 9780226702728 |
Download Stars as Laboratories for Fundamental Physics Book in PDF, ePub and Kindle
Much of what we know about neutrinos is revealed by astronomical observations, and the same applies to the axion, a conjectured new particle that is a favored candidate for the main component of the dark matter of the universe.
Author | : B. Lee Roberts |
Publisher | : World Scientific |
Total Pages | : 772 |
Release | : 2010 |
Genre | : Science |
ISBN | : 9814271845 |
Download Lepton Dipole Moments Book in PDF, ePub and Kindle
This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many of the leading authors in this field, cover both the experimental and theoretical aspects of these topics. Sample Chapter(s). Chapter 1: Historical Introduction to Electric and Mangnetic Moments (367 KB). Contents: Historical Introduction (B L Roberts); Electromagnetic Dipole Moments and New Physics (A Czarnecki & W J Marciano); Lepton g OCo 2 from 1947 to Present (T Kinoshita); Analytic QED Calculations of the Anomalous Magnetic Moment of the Electron (S Laporta & E Remiddi); Measurements of the Electron Magnetic Moment (G Gabrielse); Determining the Fine Structure Constant (G Gabrielse); Helium Fine Structure Theory for the Determination of (K Pachucki & J Sapirstein); Hadronic Vacuum Polarization and the Lepton Anomalous Magnetic Moments (M Davier); The Hadronic Light-by-Light Contribution to a, e (J Prades et al.); General Prescriptions for One-loop Contributions to a e, (K R Lynch); Measurement of the Muon ( g OCo 2) Value (J P Miller et al.); Muon ( g OCo 2) and Physics Beyond the Standard Model (D StAckinger); Probing CP Violation with Electric Dipole Moments (M Pospelov & A Ritz); The Electric Dipole Moment of the Electron (E D Commins & D DeMille); Neutron EDM Experiments (S K Lamoreaux & R Golub); Nuclear Electric Dipole Moments (W C Griffith et al.); EDM Measurements in Storage Rings (B L Roberts et al.); Models of Lepton Flavor Violation (Y Okada); Search for the Charged Lepton-Flavor-Violating Transition Moments l OaAE l OC (Y Kuno). Readership: Researchers and graduate students in particle physics, atomic physics and nuclear physics, as well as experts working in the field
Author | : Alexey N Sissakian |
Publisher | : World Scientific |
Total Pages | : 469 |
Release | : 2003-07-14 |
Genre | : Science |
ISBN | : 9814485721 |
Download Multiparticle Dynamics - Proceedings Of The Xxxii International Symposium Book in PDF, ePub and Kindle
This book covers a wide range of problems in elementary particle production physics — particle fluctuations and correlations, diffractive processes, soft and hard processes in quantum chromodynamics, heavy ion collisions, etc. Of the utmost importance are inclusion-theoretical papers devoted to the problems associated with high and even very high multiplicity particle production, making proposals for experiments at existing and forthcoming colliders of elementary particles.
Author | : Yale University. Cowles Foundation for Research in Economics |
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Total Pages | : 80 |
Release | : 1959 |
Genre | : Economics |
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Download Report of Research Activities Book in PDF, ePub and Kindle
Author | : Alexey A. Petrov |
Publisher | : CRC Press |
Total Pages | : 167 |
Release | : 2021-05-04 |
Genre | : Science |
ISBN | : 0429687397 |
Download Indirect Searches for New Physics Book in PDF, ePub and Kindle
This is the first book to discuss the search for new physics in charged leptons, neutrons, and quarks in one coherent volume. The area of indirect searches for new physics is highly topical; though no new physics particles have yet been observed directly at the Large Hadron Collider at CERN, the methods described in this book will provide researchers with the necessary tools to keep searching for new physics. It describes the lines of research that attempt to identify quantum effects of new physics particles in low-energy experiments, in addition to detailing the mathematical basis and theoretical and phenomenological methods involved in the searches, whilst making a clear distinction between model-dependent and model-independent methods employed to make predictions. This book will be a valuable guide for graduate students and early-career researchers in particle and high energy physics who wish to learn about the techniques used in modern predictions of new physics effects at low energies, whilst also serving as a reference for researchers at other levels. Key features: • Takes an accessible, pedagogical approach suitable for graduate students and those seeking an overview of this new and fast-growing field • Illustrates common theoretical trends seen in different subfields of particle physics • Valuable both for researchers in the phenomenology of elementary particles and for experimentalists