Search for Dimuon Decays of a Light Scalar Boson in Radiative Transitions Y -] Gamma A^0
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Published: 2009
Total Pages: 11
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Published: 2009
Total Pages: 11
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Published: 2009
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Published: 2008
Total Pages: 17
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DOWNLOAD EBOOKWe 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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Published: 2013
Total Pages: 139
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DOWNLOAD EBOOKWe search for di-muon decays of a low-mass Higgs boson (A0) in the fully reconstructed decay chain of [Upsilon](2S, 3S) 2![pi]+[pi]-[Upsilon](1S), [Upsilon](1S) 2![gamma]A0, A0 2![mu]+[mu]+. The A0 is predicted by several extensions of the Standard Model (SM), including the Next-to-Minimal Supersymmetric Standard Model (NMSSM). NMSSM introduces a CP-odd light Higgs boson whose mass could be less than 10 GeV/c2. The data samples used in this analysis contain 92.8 × 106 [Upsilon](2S) and 116.8 × 106 [Upsilon](3S) events collected by the BABAR detector. The [Upsilon](1S) sample is selected by tagging the pion pair in the [Upsilon](2S, 3S) 2![pi]+[pi]-[Upsilon](1S) transitions. We find no evidence for A0 production and set 90% confidence level (C.L.) upper limits on the product branching fraction B([Upsilon](1S) 2![gamma]A0) × B(A0 2![mu]+[mu]- ) in the range of (0.28 - 9.7) × 10-6 for 0.212 d"mA0 d"9.20 GeV/c2. We also combine our results with previous BABAR results of [Upsilon](2S, 3S) 2![gamma]A0, A0 2![mu]+[mu]- to set limits on the effective coupling (f[Upsilon]) of the b-quark to the A0, f 2 [Upsilon] × B(A0 2![mu]+[mu]- ), at the level of (0.29- 40) × 10-6 for 0.212 d"mA0 d"9.2 GeV/c2.
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Published: 2002
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DOWNLOAD EBOOKAfter a brief review of the puzzling light scalar meson sector of QCD, a brief summary will be given of a paper concerning radiative decays involving the light scalars. There, a simple vector meson dominance model is constructed in an initial attempt to relate a large number of the radiative decays involving a putative scalar nonet to each other. As an application it is illustrated why a0(980)-f0(980) mixing is not expected to greatly alter the f0/a0 production ratio for radiative [phi] decays.
Author: G. L. Kane
Publisher: World Scientific
Published: 2010
Total Pages: 604
ISBN-13: 9814307505
DOWNLOAD EBOOKSupersymmetry is at an exciting stage of development. It extends the Standard Model of particle physics into a more powerful theory that both explains more and allows more questions to be addressed. Most importantly, it opens a window for studying and testing fundamental theories at the Planck scale. Experimentally we are finally entering the intensity and energy and sensitivity regions where superpartners and supersymmetric dark matter candidates are likely to be detected, and then studied. There has been progress in understanding the remarkable physics implications of supersymmetry, including the derivation of the Higgs mechanism, the unification of the Standard Model forces, cosmological connections such as a candidate for the cold dark matter of the universe and consequences for understanding the cosmological history of the universe, and more. This volume begins with an excellent pedagogical introduction to the physics and methods and formalism of supersymmetry which is accessible to anyone with a basic knowledge of the Standard Model of particle physics.Next is an overview of open questions, followed by chapters on topics such as how to detect superpartners and tools for studying them, the current limits on superpartner masses as we enter the LHC era, the lightest superpartner as a dark matter candidate in thermal and non-thermal cosmological histories, and associated Z'' physics. Most chapters have been extended and updated from the earlier edition and some are new. This superb book will allow interested physicists to understand the coming experimental and theoretical progress in supersymmetry and the implications of discoveries of superpartners, and will also help students and workers to quickly learn new aspects of supersymmetry they want to pursue.
Author: Fred Jegerlehner
Publisher: Springer Science & Business Media
Published: 2008
Total Pages: 433
ISBN-13: 3540726330
DOWNLOAD EBOOKThis book reviews the present state of knowledge of the anomalous magnetic moment a=(g-2)/2 of the muon. The muon anomalous magnetic moment is one of the most precisely measured quantities in elementary particle physics and provides one of the most stringent tests of relativistic quantum field theory as a fundamental theoretical framework. It allows for an extremely precise check of the standard model of elementary particles and of its limitations.
Author: K. W. Rothe
Publisher:
Published: 1966
Total Pages: 54
ISBN-13:
DOWNLOAD EBOOKAuthor: Helen R. Quinn
Publisher: Princeton University Press
Published: 2010-01-01
Total Pages: 293
ISBN-13: 1400835712
DOWNLOAD EBOOKIn the first fractions of a second after the Big Bang lingers a question at the heart of our very existence: why does the universe contain matter but almost no antimatter? The laws of physics tell us that equal amounts of matter and antimatter were produced in the early universe—but then something odd happened. Matter won out over antimatter; had it not, the universe today would be dark and barren. But how and when did this occur? In The Mystery of the Missing Antimatter, Helen Quinn and Yossi Nir guide readers into the very heart of this mystery—and along the way offer an exhilarating grand tour of cutting-edge physics.
Author: J. Thanh Van Tran
Publisher: Atlantica Séguier Frontières
Published: 1988
Total Pages: 616
ISBN-13: 9782863320556
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