Decay width of in the Weinberg-Salam model

Slides:

Advertisements

Similar presentations

Jørgen Beck Hansen Particle Physics Basic concepts Particle Physics.

Advertisements

Announcements 11/14 Today: 9.6, 9.8 Friday: 10A – 10E Monday: 10F – 10H 9.6 Only do differential cross-section See problem 7.7 to do most of the work for.

Lecture 10: Standard Model Lagrangian The Standard Model Lagrangian is obtained by imposing three local gauge invariances on the quark and lepton field.

Section IX Electroweak Unification. 221 Electroweak Unification  Weak Charged Current interactions explained by W  exchange.  W bosons are charged,

Topics in Contemporary Physics Basic concepts 2 Luis Roberto Flores Castillo Chinese University of Hong Kong Hong Kong SAR January 16, 2015.

Branching Ratios of B c Meson Decaying to Vector and Axial-Vector Mesons Rohit Dhir Department of Physics, Yonsei University, Seoul, Korea. Dated:21-Sept-2012.

Standard Model Lagrangian with Electro-Weak Unification The Standard Model assumes that the mass of the neutrino is zero and that it is “left handed” --

Derivation of Electro-Weak Unification and Final Form of Standard Model with QCD and Gluons  1 W 1 +  2 W 2 +  3 W 3.

P461 - particles VII1 Glashow-Weinberg-Salam Model EM and weak forces mix…or just EW force. Before mixing Bosons are massless: Group Boson Coupling Quantum.

EEE539 Solid State Electronics 5. Phonons – Thermal Properties Issues that are addressed in this chapter include:  Phonon heat capacity with explanation.

Search for resonances The fingerprints of the Top Quark Jessica Levêque, University of Arizona Top Quark Mass Measurement Top Turns Ten Symposium, Fermilab,

 -decay theory. The decay rate Fermi’s Golden Rule density of final states (b) transition (decay) rate (c) transition matrix element (a) Turn off any.

1 Yurii Maravin, SMU/CLEO Snowmass 2001 Experimental Aspects of  physics at CLEO-c measurements of fundamental quantities, tests of weak couplings and.

P461 - particles VIII1 Neutrino Physics Three “active” neutrino flavors (from Z width measurements). Mass limit from beta decay Probably have non-zero.

Elementary particles atom Hadrons Leptons Baryons Mesons Nucleons

P Spring 2003 L12Richard Kass Weak Interactions & Neutral Currents Until the the mid-1970 ’ s all known weak interaction processes could be described.

J.5.1State what is meant by deep inelastic scattering. J.5.2Analyze the results of deep inelastic scattering. J.5.3Describe what is meant by asymptotic.

Gauge Boson-Pair Production in pp Collision at 14 TeV Using ATLAS at the LHC Erez Reinherz-Aronis.

P Spring 2003 L12Richard Kass The properties of the Z 0 For about ten years the Z 0 was studied in great detail at two accelerator complexes: LEP.

P Spring 2003 L9Richard Kass Inelastic ep Scattering and Quarks Elastic vs Inelastic electron-proton scattering: In the previous lecture we saw that.

Monday, Jan. 27, 2003PHYS 5326, Spring 2003 Jae Yu 1 PHYS 5326 – Lecture #4 Monday, Jan. 27, 2003 Dr. Jae Yu 1.Neutrino-Nucleon DIS 2.Formalism of -N DIS.

Lecture 16: Beta Decay Spectrum 29/10/2003 (and related processes...) Goals: understand the shape of the energy spectrum total decay rate sheds.

Inelastic scattering When the scattering is not elastic (new particles are produced) the energy and direction of the scattered electron are independent.

Probing the Majorana Nature and CP Properties of Neutralinos Yeong Gyun Kim (Korea University) In collaboration with S.Y.Choi, B.C.Chung, J.Kalinoswski.

P Spring 2003 L5 Isospin Richard Kass

M. Cobal, PIF 2003 Resonances - If cross section for muon pairs is plotted one find the 1/s dependence -In the hadronic final state this trend is broken.

EXPERIMENTAL EVIDENCE FOR THE QUARK AND STANDARD MODELS J 5.1, 5.2, 5.3, 5.4, 5.5 A particle-arly interesting presentation by LIAM HEGARTY 2012 Edited.

M. Cobal, PIF 2003 Weak Interactions Take place between all the quarks and leptons (each of them has a weak charge) Usually swamped by the much stronger.

Neutrino-Nucleus Reactions at Medium and Low Energies [contents] 1. Neutrino and weak interaction 2. Cross section for ν-A and e-A reactions 3. EMC effect.

1 Methods of Experimental Particle Physics Alexei Safonov Lecture #3.

ELECTROWEAK UNIFICATION Ryan Clark, Cong Nguyen, Robert Kruse and Blake Watson PHYS-3313, Fall 2013 University of Texas Arlington December 2, 2013.

Physics 842, February 2006 Bogdan Popescu Presentation based on “Introduction to Elementary Particles” by David Griffiths WEAK INTERACTION (1)

Prof. M.A. Thomson Michaelmas Particle Physics Michaelmas Term 2011 Prof Mark Thomson Handout 10 : Leptonic Weak Interactions and Neutrino Deep.

Water （ H 2 O ） oxygen atom （ O ） proton （ p ） electrons （ e ） neutron （ n ） 3 quarks What the matters are made out of ? 3 quarks

10/29/2007Julia VelkovskaPHY 340a Lecture 4: Last time we talked about deep- inelastic scattering and the evidence of quarks Next time we will talk about.

Lecture 2 - Feynman Diagrams & Experimental Measurements

Lecture 4 – Quantum Electrodynamics (QED)

Lecture 3 Weak Interactions (continued) muon decay Pion decay

Today’s plan Collect homework QCD leftovers Weak Interaction.

Derivation of Electro-Weak Unification and Final Form of Standard Model with QCD and Gluons  1W1+  2W2 +  3W3.

Lecture 10: Standard Model Lagrangian

PHYS 5326 – Lecture #1 Class specifications and plans

Elastic Scattering in Electromagnetism

By: Christopher Hayes November 29, 2012

Lecture 13 – the weak force

Particle Physics Michaelmas Term 2011 Prof Mark Thomson

Section VI - Weak Interactions

We’ve worked through 2 MATHEMATICAL MECHANISMS

Announcements Exam Details: Today: Problems 6.6, 6.7

Overview The Structure of the Proton Quark-Parton Model lecture-1

P Spring 2002 L13 Richard Kass The properties of the Z0

Mixing in Weak Decays Charged Weak Current (exchange of Ws) causes one member of a weak doublet to change into the other Taus and muons therefore decay.

Physics 222 UCSD/225b UCSB Lecture 2 Weak Interactions

Section XI - The Standard Model

Lecture 4 - Transverse Optics II

王国利（Guo-Li Wang）哈尔滨工业大学

Scope Introduction Motivation Objectives

Lecture 2: Invariants, cross-section, Feynman diagrams

Nonleptonic Two Body Decays of Charmed Mesons

Handout 13 : Electroweak Unification and the W and Z Bosons

Lecture 4 - Transverse Optics II

Determination of Higgs branching ratio into

Weak interactions.

Can new Higgs boson be Dark Matter Candidate in the Economical Model

Addition of angular momentum Clebsch-Gordan coefficients

Leptonic Charged-Current Interactions

Examples of QED Processes

Presentation transcript:

Decay width of in the Weinberg-Salam model Giordano Cerizza P611 – Fall 08 2/28/2019

Standard Model of Particle Physics Electroweak interaction Late 60s Weinberg and Salam described how it would be possible to treat electromagnetic and weak interactions as different aspect of a single electroweak interaction (single coupling “e”) 2/28/2019

Electroweak Interactions: Timeline From an analysis of all the experiment on weak interactions Sudarshan and Marshak showed that the electroweak interaction is a V-A interaction The existence of the electroweak interactions was experimentally established in two stages: Discovery of the neutral currents in neutrino scattering (Gargamelle, 1973) Discovery of the W and Z bosons at SPS, CERN (U1,U2, 1983) 2/28/2019

Decay of the W Boson The coupling of the leptons to W boson are flavor-independent (i.e. it is the same for all leptons). This property is called lepton universality where with p 4-momentum, e polarization 4-vector, s spin 4-vector 2/28/2019

Decay Width: Calculations The differential decay rate is defined as V-A 2/28/2019

Decay Width: Calculations Assuming the approximations: W decays at rest  the differential decay rate simplifies to Now we need to evaluate the integral… 2/28/2019

Decay Width: Calculations For simplicity let’s assume the W boson polarization The matrix element squared is: Summing over all the possible final spin state and averaging over the initial polarization state 2/28/2019

Decay Width: Calculations Energy projection operators 2/28/2019

Decay Width: Calculations The decay rate is so approximated by Assuming 2/28/2019

Decay Width: Results GeV GeV GeV Plug in the values of the constants: The experimental full decay width (from PDG’08): GeV With a branching fraction for the decay mode Results in GeV 2/28/2019