Electroweak physics at CEPC

2019 ◽  
Vol 34 (13n14) ◽  
pp. 1940013 ◽  
Author(s):  
Zhijun Liang
Keyword(s):  
High Precision ◽  
Mass Measurement ◽  
Center Of Mass ◽  
Boson Mass ◽  
Electron Positron ◽  
Electroweak Physics ◽  
One Year

The Circular Electron–Positron Collider (CEPC) project aims to build a Circular Electron–Positron Collider capable of precision physics measurements at center-of-mass energies ranging from 90 GeV to 240 GeV. The CEPC will have a total circumference of at least one hundred kilometers and at least two interaction points. In its 10 years operation at 240 GeV, it will collect more than one million Higgs events. CEPC will also run at the [Formula: see text] pole for two years, producing more than 300 billion [Formula: see text] bosons in two years. It will also collect data around the [Formula: see text] threshold for one year, in order to perform the [Formula: see text] boson mass measurement with high precision. These datasets will boost the precision of electroweak measurements by orders of magnitude. An overview is presented of the potential of CEPC to advance precision studies of electroweak physics with an emphasis on the opportunities in [Formula: see text] and [Formula: see text] physics.

scholarly journals Review of physics results from the Tevatron: Electroweak physics

2015 ◽  
Vol 30 (06) ◽  
pp. 1541004 ◽  
Author(s):  
Ashutosh V. Kotwal ◽  
Heidi Schellman ◽  
Jadranka Sekaric
Keyword(s):  
Z Boson ◽  
W Boson ◽  
Mass Measurement ◽  
New Physics ◽  
Boson Mass ◽  
Precision Measurements ◽  
Boson Production ◽  
Physics Program ◽  
Electroweak Sector ◽  
Electroweak Physics

We summarize an extensive Tevatron (1984–2011) electroweak physics program that involves a variety of W and Z boson precision measurements. The relevance of these studies using single and associated gauge boson production to our understanding of the electroweak sector, quantum chromodynamics and searches for new physics is emphasized. We discuss the importance of the W boson mass measurement, the W/Z boson distributions and asymmetries, and diboson studies. We highlight the recent Tevatron measurements and prospects for the final Tevatron measurements.

scholarly journals Search for the rare semi-leptonic decay J/ψ → D−e+νe + c.c.

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
◽  
M. Ablikim ◽  
M. N. Achasov ◽  
P. Adlarson ◽  
S. Ahmed ◽  
...  
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Center Of Mass ◽  
Leptonic Decay ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Upper Limit ◽  
Electron Positron

Abstract Using 10.1 × 109J/ψ events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy $$ \sqrt{s} $$ s = 3.097 GeV and collected with the BESIII detector, we present a search for the rare semi-leptonic decay J/ψ → D−e+νe + c.c. No excess of signal above background is observed, and an upper limit on the branching fraction ℬ(J/ψ → D−e+νe + c. c.) < 7.1 × 10−8 is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.

The electroweak contributions to(g−2)μafter the Higgs-boson mass measurement

2013 ◽  
Vol 88 (5) ◽  
Author(s):  
C. Gnendiger ◽  
D. Stöckinger ◽  
H. Stöckinger-Kim
Keyword(s):  
Higgs Boson ◽  
Mass Measurement ◽  
Boson Mass ◽  
Higgs Boson Mass

CEPC Z-pole polarization design studies

2021 ◽  
pp. 2142003
Author(s):  
Wenhao Xia ◽  
Jie Gao ◽  
Yiwei Wang ◽  
Dou Wang
Keyword(s):  
Beam Energy ◽  
Center Of Mass ◽  
Transverse Polarization ◽  
Beam Polarization ◽  
Energy Measurement ◽  
Design Studies ◽  
Electron Positron ◽  
Polarized Beam ◽  
Different Types ◽  
Schematic Design

In this paper, we give preliminary designs of beam polarization manipulations by inserting three different types of insertions in the Circular Electron–Positron Collider (CEPC) at center-of-mass energies of 91 GeV (Z-pole). With the wigglers in the collider ring, we can obtain 5% transverse polarization in 1.1 h for the precise energy measurement. To overcome depolarization effects as the beam energy rises from 10 GeV to 45.5 GeV in the booster ring, Siberian snakes based on helical magnets are adopted. Finally, for longitudinally polarized beam collisions, a schematic design of spin rotators based on solenoids in the collider ring is studied.

scholarly journals High-precision mass measurement of neutron-rich 96Kr

2020 ◽  
Vol 241 (1) ◽  
Author(s):  
Matthew B. Smith ◽  
Tobias Murböck ◽  
Eleanor Dunling ◽  
Andrew Jacobs ◽  
Brian Kootte ◽  
...  
Keyword(s):  
High Precision ◽  
Mass Measurement ◽  
Precision Mass Measurement

An updated matrix to predict rapid radiographic progression of early rheumatoid arthritis patients: pooled analyses from several databases

Rheumatology ◽  
2019 ◽  
Vol 59 (8) ◽  
pp. 1842-1852 ◽  
Author(s):  
Antoine Vanier ◽  
Josef S Smolen ◽  
Cornelia F Allaart ◽  
Ronald Van Vollenhoven ◽  
Patrick Verschueren ◽  
...  
Keyword(s):  
High Precision ◽  
Radiographic Progression ◽  
Area Under The Curve ◽  
X Rays ◽  
Early Ra ◽  
The Matrix ◽  
Moderate Sensitivity ◽  
Baseline Characteristics ◽  
One Year ◽  
Post Hoc

Abstract Objective In early RA, some patients exhibit rapid radiographic progression (RRP) after one year, associated with poor functional prognosis. Matrices predicting this risk have been proposed, lacking precision or inadequately calibrated. We developed a matrix to predict RRP with high precision and adequate calibration. Methods Post-hoc analysis by pooling individual data from cohorts (ESPOIR and Leuven cohorts) and clinical trials (ASPIRE, BeSt and SWEFOT trials). Adult DMARD-naïve patients with active early RA for which the first therapeutic strategy after inclusion was to prescribe methotrexate or leflunomide were included. A logistic regression model to predict RRP was built. The best model was selected by 10-fold stratified cross-validation by maximizing the Area Under the Curve. Calibration and discriminatory power of the model were checked. The probabilities of RRP for each combination of levels of baseline characteristics were estimated. Results 1306 patients were pooled. 20.6% exhibited RRP. Four predictors were retained: rheumatoid factor positivity, presence of at least one RA erosion on X-rays, CRP &gt; 30mg/l, number of swollen joints. The matrix estimates RRP probability for 36 combinations of level of baseline characteristics with a greatly enhanced precision compared with previously published matrices (95% CI: from ± 0.02 minimum to ± 0.08 maximum) and model calibration is excellent (P = 0.79). Conclusion A matrix proposing RRP probability with high precision and excellent calibration in early RA was built. Although the matrix has moderate sensitivity and specificity, it is easily usable and may help physicians and patients to make treatment decisions in daily clinical practice.

scholarly journals Prospects for improving the LHC W boson mass measurement with forward muons

2015 ◽  
Vol 75 (12) ◽  
Author(s):  
Giuseppe Bozzi ◽  
Luca Citelli ◽  
Mika Vesterinen ◽  
Alessandro Vicini
Keyword(s):  
W Boson ◽  
Mass Measurement ◽  
Boson Mass

MOMENTUM DISTRIBUTION OF METALLIC ELECTRONS BY POSITRON ANNIHILATION

1957 ◽  
Vol 35 (2) ◽  
pp. 168-183 ◽  
Author(s):  
A. T. Stewart
Keyword(s):  
Positron Annihilation ◽  
Momentum Distribution ◽  
Center Of Mass ◽  
Velocity Dependence ◽  
Conduction Electrons ◽  
Two Photon ◽  
Photon Decay ◽  
Electron Positron ◽  
Momentum Distributions ◽  
Annihilation Probability

The angular correlation of photons from the two-photon decay of positrons has been measured for positrons annihilating in some 34 elements, mostly metals. These data give the momentum distribution of photons and hence of the center of mass of the annihilating electron–positron pairs. The momentum distributions are discussed in terms of the velocity dependence of the annihilation probability. It is concluded that the observed momentum distributions are primarily the momentum distributions of the conduction electrons in the metals. A higher momentum component is observed, which is attributed to ion core effects.

scholarly journals Prospects for rare and forbidden hyperon decays at BESIII

2017 ◽  
Vol 12 (5) ◽  
Author(s):  
Hai-Bo Li
Keyword(s):  
Rare Decays ◽  
Branching Fractions ◽  
Center Of Mass ◽  
Final States ◽  
Electron Spectrometer ◽  
Mass Energy ◽  
Measurement Sensitivity ◽  
Center Of Mass Energy ◽  
Electron Positron ◽  
Hyperon Decays

Abstract The study of hyperon decays at the Beijing Electron Spectrometer III (BESIII) is proposed to investigate the events of J/ψ decay into hyperon pairs, which provide a pristine experimental environment at the Beijing Electron–Positron Collider II. About 106–108 hyperons, i.e., Λ, Σ, Ξ, and Ω, will be produced in the J/ψ and ψ(2S) decays with the proposed data samples at BESIII. Based on these samples, the measurement sensitivity of the branching fractions of the hyperon decays is in the range of 10−5–10−8. In addition, with the known center-of-mass energy and “tag technique”, rare decays and decays with invisible final states can be probed.

Relativistic Electron-Positron Gamma Ray Laser

1986 ◽  
Vol 41 (8) ◽  
pp. 1005-1008
Author(s):  
F. Winterberg
Keyword(s):  
Relativistic Electron ◽  
Gamma Ray ◽  
Center Of Mass ◽  
Rest Mass ◽  
Mass Energy ◽  
Electron Positron ◽  
Pair Annihilation ◽  
Rapid Formation ◽  
Time Requirements ◽  
Dense State

The prerequisite for an efficient electron-positron gamma ray laser, which is the rapid formation o f a dense electron-positron plasma in a time shorter than the time for pair annihilation, is ideally fulfilled in a relativistic electron-positron superpinch. Because the cross section for annihilation decreases quadratically with the center o f mass energy, the time requirements otherwise imposed, are greatly relaxed. A relativistic electron-positron pinch can collapse under a complete population inversion into a very dense state possessing the form o f a long filament, just as it is required for a gamma ray laser. The gamma ray energies are the total center of mass energies, which can be much larger than the electron-positron rest mass energies.

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