scholarly journals Probe of the Anomalous Quartic Couplings with Beam Polarization at the CLIC

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
A. Senol ◽  
M. Köksal ◽  
S. C. İnan
Keyword(s):  
Confidence Level ◽  
Semileptonic Decay ◽  
Linear Collider ◽  
Decay Channel ◽  
Center Of Mass ◽  
Positron Beam ◽  
Beam Polarization ◽  
Electron Positron ◽  
Integrated Luminosity

We have investigated the anomalous quartic couplings defined by the dimension-8 operators in semileptonic decay channel of thee+e-→νeW-W+ν-eprocess for unpolarized and polarized electron (positron) beam at the Compact Linear Collider. We give the 95% confidence level bounds on the anomalousfS0/Λ4,fS1/Λ4, andfT0/Λ4couplings for various values of the integrated luminosities and center-of-mass energies. The best sensitivities obtained on anomalousfS0/Λ4,fS1/Λ4, andfT0/Λ4couplings through the processe+e-→νeW-W+ν-ewith beam polarization ats=3 TeV and an integrated luminosity ofLint=2000 fb-1are[-4.05;3.67]×10-12 GeV-4,[-3.08;2.12]×10-12 GeV-4, and[-1.98;0.64]×10-13 GeV-4, which show improvement over the current bounds.

scholarly journals The measurement of the $$H\rightarrow \tau \tau $$ signal strength in the future $$e^{+}e^{-}$$ Higgs factories

2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Dan Yu ◽  
Manqi Ruan ◽  
Vincent Boudry ◽  
Henri Videau ◽  
Jean-Claude Brient ◽  
...  
Keyword(s):  
Linear Collider ◽  
Simulation Analysis ◽  
Center Of Mass ◽  
International Linear Collider ◽  
Signal Strength ◽  
Relative Accuracy ◽  
Hadronic Decay ◽  
Beam Polarization ◽  
Baseline Design ◽  
Electron Positron

AbstractThe Circular Electron Positron Collider and the International Linear Collider are two electron-positron Higgs factories. They are designed to operate at a center-of-mass energy of 240 and 250 GeV and accumulate 5.6 and 2 $$ab^{-1}$$ab-1 of integrated luminosity. This paper estimates their performance on the $$H \rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- benchmark measurement. Using the full simulation analysis, the CEPC is expected to measure the signal strength to a relative accuracy of 0.8%. Extrapolating to the ILC setup, we conclude the ILC can reach a relative accuracy of 1.1% or 1.2%, corresponding to two benchmark beam polarization setups. The physics requirement on the mass resolution of the Higgs boson with hadronic decay final states is also discussed, showing that the CEPC baseline design and reconstruction fulfill the accuracy requirement of the $$H\rightarrow \tau ^{+}\tau ^{-}$$H→τ+τ- signal strength.

FIRST MEASUREMENT OF THE LEFT-RIGHT ASYMMETRY IN Z-BOSON PRODUCTION

1993 ◽  
Vol 08 (24) ◽  
pp. 2237-2248 ◽  
Author(s):  
◽  
K. ABE ◽  
I. ABT ◽  
P. D. ACTON ◽  
C. E. ADOLPHSEN ◽  
...  
Keyword(s):  
Z Boson ◽  
Linear Collider ◽  
Center Of Mass ◽  
Positron Beam ◽  
Beam Polarization ◽  
Boson Production ◽  
Weak Mixing Angle ◽  
Center Of Mass Energy ◽  
Average Electron ◽  
Left Right Asymmetry

We present the first measurement of the left-right cross-section asymmetry (A LR ) in Z-boson production observed at the SLAC Linear Collider. In 1992 the SLD detector recorded 10 224 Z events produced by the collision of longitudinally polarized electrons with an unpolarized positron beam at a center-of-mass energy of 91.55 GeV. The average electron beam polarization during the run was (22.4 ± 0.6)%. We measure A LR to be 0.100 ± 0.0440 (stat.) ±0.004 (syst.) , which determines the effective weak mixing angle to be [Formula: see text].

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.

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 PROGRESS WITH THE JLC/NLC X-BAND LINEAR COLLIDER DESIGN

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1193-1196
Author(s):  
T. O. Raubenheimer
Keyword(s):  
Linear Collider ◽  
Center Of Mass ◽  
Cost Savings ◽  
Significant Cost ◽  
Center Of Mass Energy ◽  
Physics Program ◽  
Electron Positron ◽  
X Band ◽  
Beam Delivery ◽  
Beam Delivery System

An electron/positron linear collider with a center-of-mass energy between 0.5 and 1 TeV would be an important complement to the physics program of the LHC in the next decade. The Next Linear Collider (NLC) is being designed by a US collaboration (FNAL, LBNL, LLNL, and SLAC) which is working closely with the Japanese collaboration that is designing the Japanese Linear Collider (JLC). This paper will discuss the technical difficulties encountered as well as the changes that have been made to the NLC design over the last year. These changes include improvements to the X-band rf system as well as modifications to the beam delivery system. The net effect has been to reduce the length of the collider from about 32 km to 25 km and to reduce the number of klystrons and modulators by a factor of two. Together these lead to significant cost savings.

RECENT RESULTS FROM LEP

1993 ◽  
Vol 08 (08) ◽  
pp. 675-695 ◽  
Author(s):  
GÜNTER QUAST
Keyword(s):  
Standard Model ◽  
Center Of Mass ◽  
Electroweak Interaction ◽  
Electron Positron ◽  
Main Emphasis ◽  
The Standard Model ◽  
Large Electron Positron ◽  
Integrated Luminosity

Recent results from the four experiments ALEPH, DELPHI, L3 and OPAL at the large electron-positron collider, LEP, at CERN are reviewed. Analyzes from an integrated luminosity of about 20 pb −1 per experiment, taken at different center-of-mass energies within ±3 GeV around the Z0 resonance, are available now. Here, the main emphasis is put on the relevance of these measurements for precision tests of the Standard Model of the electroweak interaction.

DEPOLARIZATION AND LUMINOSITY ISSUES IN A HIGH ENERGY LINEAR COLLIDER

2000 ◽  
Vol 15 (16) ◽  
pp. 2555-2564
Author(s):  
S. CHESHKOV ◽  
T. TAJIMA
Keyword(s):  
Linear Collider ◽  
Center Of Mass ◽  
High Energy ◽  
Collision Point ◽  
Single Beam ◽  
Center Of Mass Energy ◽  
Electron Positron ◽  
Spin Depolarization ◽  
Positron Beams ◽  
Energy Frontier

In the next energy frontier of an electron–positron (electron–electron) linear collider its demand of both extreme high energy and high luminosity leads to a high production of W+W- (W- particles). In order to delineate processes of interest, it is advantageous to polarize the electron and positron beams, as this tends to suppress the above known processes and thus heightens the sensitivity to the sought-after processes. We investigate the possible depolarization of the electron (positron) beams in the acceleration stages as well as in the collision point. We take the example of the laser wakefield accelerator design at 5 TeV center of mass energy of colliding beams. We find that in this design the spin depolarization due to the stage jitter noise is certainly negligible, and the depolarization due to the self-generated fields at the collision point is still tolerable. We also consider several lower energy scenarios as they might be possible to achieve in a single beam driven acceleration stage.

scholarly journals Tau $$g{-}2$$ at $$e^-e^+$$ colliders with momentum-dependent form factor

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Hieu Minh Tran ◽  
Yoshimasa Kurihara
Keyword(s):  
Form Factor ◽  
Linear Collider ◽  
International Linear Collider ◽  
Large Mass ◽  
New Physics ◽  
Magnetic Form Factor ◽  
Beam Polarization ◽  
Electron Positron ◽  
Dependent Form ◽  
Model Independent

AbstractThe deviation between the prediction based on the standard model and the measurement of the muon $$g{-}2$$ g - 2 is currently at $$3{-}4 \sigma $$ 3 - 4 σ . If this discrepancy is attributable to new physics, it is expected that the new contributions to the tau $$g{-}2$$ g - 2 even larger than those of muon due to its large mass. However, it is much more difficult to directly measure the tau $$g{-}2$$ g - 2 because of its short lifetime. In this report, we consider the effect of the tau $$g{-}2$$ g - 2 at $$e^-e^+$$ e - e + colliders using a model independent approach. Using the tau pair production channel at the Large Electron Position Collider (LEP), we have determined the allowed range for the new physics contribution of the tau $$g{-}2$$ g - 2 assuming a q-square-dependence ansatz for the magnetic form factor. We also investigated the prospect at future $$e^+e^-$$ e + e - colliders, such as International Linear Collider, the Compact Linear Collider, the Future Circular $$e^+e^-$$ e + e - Collider, and Circular Electron Positron Collider, and determined the expected allowed range for the new physics contribution to the tau anomalous magnetic moment. The best limits are about $$4{-}5$$ 4 - 5 times more severe than the LEP one due to the beam polarization and the high luminosities at future colliders.

scholarly journals Measurements of angular distance and momentum ratio distributions in three-jet and $${\text {Z}}$$ + two-jet final states in $${\text {p}}{\text {p}}$$ collisions

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
M. Dragicevic ◽  
...  
Keyword(s):  
Cross Sections ◽  
Decay Channel ◽  
Production Cross ◽  
Center Of Mass ◽  
Large Angle ◽  
Angular Separation ◽  
Angular Distance ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Integrated Luminosity

AbstractCollinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and $${\text {Z}}$$ Z  + two-jet events collected in proton-proton collisions at the LHC. The normalized production cross sections are measured as a function of the ratio of transverse momenta of two jets and their angular separation. The measurements in the three-jet and $${\text {Z}}$$ Z  + two-jet events are based on data collected at a center-of-mass energy of 8$$\,{\text {TeV}}$$ TeV , corresponding to an integrated luminosity of 19.8$$\,\text {fb}^{-1}$$ fb - 1 . The $${\text {Z}}$$ Z  + two-jet events are reconstructed in the dimuon decay channel of the $${\text {Z}}$$ Z  boson. The three-jet measurement is extended to include $$\sqrt{s} = 13\,{\text {TeV}} $$ s = 13 TeV data corresponding to an integrated luminosity of 2.3$$\,\text {fb}^{-1}$$ fb - 1 . The results are compared to predictions from event generators that include parton showers, multiple parton interactions, and hadronization. The collinear and soft regions are in general well described by parton showers, whereas the regions of large angular separation are often best described by calculations using higher-order matrix elements.

NEXT LINEAR COLLIDER: OVERVIEW AND e-e- OPTION

2000 ◽  
Vol 15 (16) ◽  
pp. 2461-2468
Author(s):  
P. TENENBAUM
Keyword(s):  
Large Hadron Collider ◽  
Room Temperature ◽  
Permanent Magnets ◽  
Linear Collider ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Electron Collisions ◽  
Rf Systems ◽  
Electron Positron ◽  
Positron Collisions

A lepton collider capable of generating a luminosity of 5×1033 to 1×1034 at center-of-mass energies from 0.5 to 1.5 TeV would permit studies of fundamental interactions complementary to those planned at the Large Hadron Collider. Such energies would be more easily achieved for electrons at a linear collider than a conventional storage ring. We describe the Next Linear Collider (NLC), a proposed linear collider which utilizes room-temperature RF systems operating at 11.4 GHz to achieve the desired energies and room-temperature electromagnets and permanent magnets to achieve the extremely small beam sizes required to meet the specified luminosity goal. The NLC design has been optimized to permit electron–electron collisions as well as electron–positron collisions. We discuss a few of the detailed technical challenges which are posed by electron–electron collisions in the NLC parameter regime.

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