Decays of the Tau Lepton

Decays of the Tau Lepton PDF Author: Patricia Burchat
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Leptons (Nuclear physics)
Languages : en
Pages : 292

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Book Description

Decays of the Tau Lepton

Decays of the Tau Lepton PDF Author: Patricia Burchat
Publisher: Ann Arbor, Mich. : University Microfilms International
ISBN:
Category : Leptons (Nuclear physics)
Languages : en
Pages : 292

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Book Description


Decays of the Tau Lepton

Decays of the Tau Lepton PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Previous measurements of the branching fractions of the tau lepton result in a discrepancy between the inclusive branching fraction and the sum of the exclusive branching fractions to final states containing one charged particle. The sum of the exclusive branching fractions is significantly smaller than the inclusive branching fraction. In this analysis, the branching fractions for all the major decay modes are measured simultaneously with the sum of the branching fractions constrained to be one. The branching fractions are measured using an unbiased sample of tau decays, with little background, selected from 207 pb−1 of data accumulated with the Mark II detector at the PEP ee− storage ring. The sample is selected using the decay products of one member of the .gamma.gamma.− pair produced in e+e− annihilation to identify the event and then including the opposite member of the pair in the sample. The sample is divided into subgroups according to charged and neutral particle multiplicity, and charged particle identification. The branching fractions are simultaneously measured using an unfold technique and a maximum likelihood fit. The results of this analysis indicate that the discrepancy found in previous experiments is possibly due to two sources. First, the leptonic branching fractions measured in this analysis are about one standard deviation higher than the world average. The measured leptonic branching fractions correspond to a tau lifetime of (3.0 +- 0.2) x 10−13 s. Secondly, the total branching fraction to one charged hadron plus at least one neutral particle is measured to be (7 +- 3)% higher than the branching fraction expected from a combination of previous measurements and theoretical predictions. It is shown that decay modes involving the eta are not expected to contribute more than 3% to this excess.

Particle Physics And Cosmology - Proceedings Of The Ninth Lake Louise Winter Institute

Particle Physics And Cosmology - Proceedings Of The Ninth Lake Louise Winter Institute PDF Author: D Page
Publisher: World Scientific
ISBN: 9814549851
Category :
Languages : en
Pages : 570

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Book Description
This volume explores the recent trends in particle physics and cosmology. The invited lecturers include D Caldwell, A Linde, A B MacDonald, J Peebles, K Rolfs and D Schramm.

Gauge Theory of Weak Decays

Gauge Theory of Weak Decays PDF Author: Andrzej J. Buras
Publisher: Cambridge University Press
ISBN: 1107034035
Category : Science
Languages : en
Pages : 739

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Book Description
"The ultimate question of elementary particle physics is: What is the fundamental Lagrangian of nature surrounding us? The Lagrangian of the SM is very successful in describing nature at the currently available energy range. The discovery of the Higgs boson completed the particle spectrum of the SM and it is another proof of how well the SM works. Nevertheless the SM cannot be the end of the story and it is for sure not the fundamental Lagrangian of nature. The Lagrangian of the SM looses its validity at the latest at the Planck scale where gravitational effects become noticeable.Most physicists think of the SM as an effective theory that has to be replaced by a more fundamental theory above the TeV scale. What the word effective really means will hopefully be clear at later stages of our book. For the time being we will list some problems and open questions of the SM"--

High Energy Physics

High Energy Physics PDF Author: Glenn Cunningham
Publisher: Scientific e-Resources
ISBN: 1839473851
Category :
Languages : en
Pages : 316

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Book Description
Particle physics (also high energy physics) is the branch of physics that studies the nature of the particles that constitute matter and radiation. Although the word "e;particle"e; can refer to various types of very small objects "e;particle physics"e; usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model. Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "e;known"e; particle, the Higgs boson, or even to the oldest known force field, gravity. Written in a clear pedagogic style by active researchers, this book will prepare a beginner to work in the field and at the same time will also provide useful reference material for active researchers.

The Physics of the Z and W Bosons

The Physics of the Z and W Bosons PDF Author: Roberto Tenchini
Publisher: World Scientific
ISBN: 9812707026
Category : Science
Languages : en
Pages : 436

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Book Description
This book describes the memorable theoretical work that motivated the construction of the electron-positron accelerators at CERN and SLAC, and the monumental experimental effort that led to a verification of the main theoretical expectations at these laboratories and at Fermilab.The aim is to provide a description of the theoretical work, as well as a synthesis of the experimental effort, which makes interesting reading for both theorists and experimentalists. In particular, the experimental measurements, discussed in the second part of the book, are systematically related to the theoretical quantities discussed in the first. The topics still to be investigated, unsolved problems, and the perspectives at future giant accelerators conclude this fascinating text.

Decays of the Heavy Lepton, Tau (1785).

Decays of the Heavy Lepton, Tau (1785). PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The structure of the weak hadronic current coupled to the tau is investigated via some of the hadronic decays of the tau. The vector current coupling is determined by measuring the tau .-->. rho .nu./sub tau/ branching ratio. The axial-vector coupling is determined by measuring the tau .-->. .pi. .nu./sub tau/ branching ratio. The Cabibbo structure of the hadronic current is established by observing the decay tau .-->. K*(890).nu./sub tau/ and measuring its branching ratio. The branching ratios for the decays tau .-->. e anti .nu./sub e/.nu./sub tau/ and tau .-->. .mu. anti .nu./sub .mu./.nu./sub tau/ are measured as a normalization for the hadronic decays and as a check on the validity of the measurements. The leptonic branching ratios agree well with previous experiments. From a kinematic fit to the pion energy spectrum in the decay tau .-->. .pi. .nu./sub tau/, an upper limit (95% confidence level) of 245 MeV is placed on the tau neutrino mass. From a simultaneous fit of the center of mass energy dependence of the tau production cross section and the pion energy spectrum in the decay tau .-->. .pi. .nu./sub tau/, the tau mass is determined to be 1.787 +- 010 GeV/c. All properties of the tau measured here are consistent with it being a sequential lepton coupled to the ordinary weak hadronic current.

Search for Dark Matter with the ATLAS Detector

Search for Dark Matter with the ATLAS Detector PDF Author: Johanna Gramling
Publisher: Springer
ISBN: 3319950169
Category : Science
Languages : en
Pages : 290

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Book Description
This book discusses searches for Dark Matter at the CERN’s LHC, the world’s most powerful accelerator. It introduces the relevant theoretical framework and includes an in-depth discussion of the Effective Field Theory approach to Dark Matter production and its validity, as well as an overview of the formalism of Simplified Dark Matter models. Despite overwhelming astrophysical evidence for Dark Matter and numerous experimental efforts to detect it, the nature of Dark Matter still remains a mystery and has become one of the hottest research topics in fundamental physics. Two searches for Dark Matter are presented, performed on data collected with the ATLAS experiment. They analyze missing-energy final states with a jet or with top quarks. The analyses are explained in detail, and the outcomes and their interpretations are discussed, also in view of the precedent analysis of theoretical approaches. Given its depth of coverage, the book represents an excellent reference guide for all physicists interested in understanding the theoretical and experimental considerations relevant to Dark Matter searches at the LHC.

Dawn Of The Lhc Era, The (Tasi 2008) - Proceedings Of The 2008 Theoretical Advanced Study Institute In Elementary Particle Physics

Dawn Of The Lhc Era, The (Tasi 2008) - Proceedings Of The 2008 Theoretical Advanced Study Institute In Elementary Particle Physics PDF Author: Tao Han
Publisher: World Scientific
ISBN: 9814468827
Category : Science
Languages : en
Pages : 773

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Book Description
This book contains material from the lecture courses conducted at the Theoretical Advanced Study Institute (TASI, Colorado, USA) on high energy physics and cosmology in 2008. Three series of lectures are presented in parallel in the areas of Large Hadron Collider (LHC) phenomenology and experimentation; advanced theoretical topics beyond the standard model; and neutrino oscillation, astroparticle physics and cosmology. The phenomenology lectures cover a broad spectrum of standard research techniques used to interpret present-day and LHC data. The new physics lectures focus on modern speculations about physics beyond the standard model, with an emphasis on supersymmetry, grand unification theories, extra-dimensional theories, and string phenomenology, which may be tested at the LHC. The lecture series on neutrino physics, astroparticle physics and cosmology treats recent developments in neutrino oscillations, theories and searches of dark matter and dark energy, cosmic microwave background radiation, and density perturbation theory. The lectures are of pedagogical nature in presentation, and are accessible to advanced graduate students and researchers in high energy physics and cosmology.

'97 QCD and High Energy Hadronic Interactions

'97 QCD and High Energy Hadronic Interactions PDF Author: J. Thanh Van Tran
Publisher: Atlantica Séguier Frontières
ISBN: 9782863322253
Category : Technology & Engineering
Languages : en
Pages : 690

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Book Description