This chapter of the report of the “Flavor in the era of the LHC” Workshop discusses the theoretical, phenomenological and experimental issues related to flavor phenomena in the charged lepton sector and in flavor conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavor structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the standard model, presenting benchmarks for the discovery potential of forthcoming measurements both at the LHC and at low energy, and exploring options for possible future experiments.

/pdf/flavor-physics-of-leptons-and-dipole-moments-26infwadhn.pdf

Flavor physics of leptons and dipole moments

pdf/measurement-of-the-tau-polarisation-at-lep-melpcdfl1n.pdf

Measurement of the Tau Polarisation at LEP

The Standard Model of Particle Physics (SM) postulates the universal coupling of the three lepton families to the weak current. The most precise measurement of lepton universality in W± decays comes from the four experiments at the Large Electon-Positron Collider (LEP). If one compares the couplings of muons and tau leptons to the charged weak current, there is a discrepancy of nearly three standard deviations w.r.t. the SM expectation. There are models beyond the SM, which could explain the violation of lepton universality with new physics processes, if it is more than a statistical fluctuation. The Large Hadron Collider (LHC) offers a great opportunity to study decays of the chargedweak gauge bosons at very high event rates and at unmatched collision energies. This thesis presents an analysis strategy to test lepton universality with the Compact Muon Solenoid experiment (CMS) at the LHC. The analysis focusses on the decays of the W± boson to particles of the second and third lepton family. For this purpose detector-simulated proton-proton events are used. The identification and reconstruction of tau leptons is a difficult task at the LHC. The reconstruction is often restricted by the limited precision of the commonly used collinear approximation. The application of a kinematic fit to particular tau-decay modes can improve the experimental resolution and provides an efficient background suppression. The development of such a fit with kinematic constraints derived from the topology of the decay τ → 3π±+ ντ is described. The kinematic fit of tau leptons is not limited to the test for lepton universality, but can be deployed by various physics analyses in a broad energy range of the tau leptons. The event topology of W± decays with leptonic final states is studied. Two event selections are developed: one for the W± → τν and one for the W± → μν decay. A common online selection is proposed, which is independent of the leptonic final state of the W± bosons. The selection of W± → τν events uses the developed kinematic fit of tau leptons. The selection of W±-boson decays is done by a set of requirements on decay-specific event characteristics. Each of these criteria is introduced, and its impact on the selection of signal and background processes is reviewed. The efficiencies and purities are derived, and statistical and systematic uncertainties are discussed. The sensitivity of CMS to lepton universality is estimated.

Kinematic Reconstruction of Tau Leptons and Test for Lepton Universality in Charged Weak Interactions with the CMS Experiment

We study various $\alpha $
 -decay chains on the basis of the preformed cluster decay model. Our work targets the superheavy elements, which are expected to show extra stability at shell closure. Our computations identify the following combinations of proton and neutron numbers as the most stable nuclei: $Z=112$
 , $N=161, 163$
 ; $Z=114$
 , $N=171, 178, 179$
 ; and $Z=124$
 , $N=194$
 . We also investigate the alternative of heavy cluster emissions in the decay chain of 301120, instead of $\alpha $
 decay. Our study of cluster radioactivity shows that the half-life for 10Be decay in 289114 is larger, indicating enhanced stability at $Z=114$
 , $N=175$
 . Similar calculations concerning the emission of $\ ^{14}{\rm C}$
 and $\ ^{34}{\rm Si}$
 from 301120 find the more stable combinations $Z=114$
 , $N=173$
 , and $Z=106$
 , $N=161$
 , respectively. From the same parent, 301120, the emission of a $\ ^{49-51}{\rm Ca}$
 cluster yielding a $Z=100$
 , $N=152$
 daughter is the most probable.

Study of Alpha Decay Chains of Superheavy Nuclei and Magic Number Beyond Z = 82 and N = 126

Searches for the pair production of supersymmetric particles under the assumption that R-parity is violated via a single dominant LLEbar, LQDbar or UbarDbarDbar coupling are performed using the data collected by the ALEPH detector at LEP at centre-of-mass energies from 189 to 209Gev. The numbers of observed candidate events in the data are in agreement with the Standard Model expectation, and limits on the production cross sections and on the masses of charginos, sleptons, squarks and sneutrinos are derived.

/pdf/search-for-supersymmetric-particles-with-r-parity-violating-1uzzxaog2q.pdf

Search for supersymmetric particles with R-parity violating decays in e(+)e(-) collisions at root s up to 209 GeV

Search for R-parity violation with a U D D coupling at p s = 189 GeV

The τ polarisation has been studied with the e+e− → τ+τ− data collected by the DELPHI detector at LEP in 1993, 1994 and 1995 around the Z resonance firstly through the exclusive decay channels eνν̄, μνν̄, πν, ρν and a1ν and secondly with an inclusive hadronic analysis which benefits from a higher efficiency and a better systematic precision. The results have been combined with those previously published on 1990 to 1992 DELPHI data, to produce results which reflect the full LEP-1 statistics. The fit of the τ polarisation dependence on the production angle yielded the polarisation parameters Aτ = 0.1359 ± 0.0096 and Ae = 0.1382 ± 0.0116. From these results the ratio of the vector and axial-vector effective couplings v̄τ/āτ = 0.0683 ± 0.0048 and v̄e/āe = 0.0694 ± 0.0058 have been derived, compatible with e−τ universality. With the assumption of lepton universality, the ratio of vector to axial-vector effective couplings for leptons v̄l/āl = 0.0687 ± 0.0037 was obtained, implying a value of the effective weak mixing angle sin θ eff = 0.23282 ± 0.00092.

http://theor.jinr.ru/people/Sissakian/CV/public/2000/Eur.Phys.J.2000_C14_p585.pdf

A precise measurement of the polarisation at LEP-1

Measurement of the W-pair production cross-section and W branching ratios in e + e collisions at p s =

Identied Charged Particles and Resonances in Quark

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

W. Adam

Author Tools

Chat about Author

Papers

Search for R-parity violation with a U D D coupling at p s = 189 GeV

A precise measurement of the polarisation at LEP-1

Measurement of the W-pair production cross-section and W branching ratios in e + e collisions at p s =

Identied Charged Particles and Resonances in Quark