India at CERN: pre-LHC Gurtu, A.
The European physical journal. ST, Special topics,
12/2023, Letnik:
232, Številka:
17
Journal Article
Recenzirano
The history of India–CERN engagement is traced from the time of inception and establishment of CERN as an important player in the field of particle physics. Indian groups were involved in a number of ...CERN-based experiments during the 1960s, 70s and 80s. During the 1990s, the Indian funding agencies (Departments of Atomic Energy (DAE) and Science and Technology (DST)) came together to ensure a comprehensive Indian participation in the LHC project, with many Indian physics groups participating in the ALICE and CMS collaborations and a number of DAE institutions contributing towards the construction of the LHC machine.
Fourteen independent couplings, seven each for ZWW and γWW, completely describe the VWW vertices within the most general framework of the electroweak Standard Model （SM） consistent with Lorentz ...invariance and U（1） gauge invariance. Of each of the seven TGCs, three conserve C and P individually, three violate CP, and one violates C and P individually while conserving CP.
Quartic couplings, WWZZ, WWZγ WWγγ, and ZZγγ, were studied at LEP and Tevatron at energies at which the Standard Model predicts negligible contributions to multiboson production. Thus, to parametrize ...limits on these couplings, an effective theory approach is adopted which supplements the Standard Model Lagrangian with higher dimensional operators which include quartic couplings. The LEP collaborations chose the lowers dimensional representation of operators （dimension 6） which presumes the SU（2）xU（1） gauge symmetry is broken by means other than the conventional Higgs scalar doublet 1-3.
THE Z BOSON M.W. Griinewald A. Gurtu
中国物理C：英文版,
2016
10
Journal Article
Recenzirano
Precision measurements at the Z-boson resonance using electron-positron colliding beams began in 1989 at the SLC and at LEP. During 1989-95, the four LEP experiments （ALEPH, DELPHI, L3, OPAL） made ...high-statistics studies of the production and decay properties of the Z. Although the SLD experiment at the SLC collected much lower statistics,
In on-shell Zγ production, deviations from the Standard Model for the Zγ＂ and ZγZ＊ couplings may be described in terms of eight parameters, hV （i = 1, 4; V = 7, Z） 1. The parameters hiγ describe the ...Zγγ＊ couplings and the parameters hz the Ziγ,ZγZ＊couplings.
Precision determination of the W-mass is of great importance in testing the internal consistency of the Standard Model. From the time of its discovery in 1983, the W-boson has been studied and its ...mass determined in pp and e＋e- interactions; it is currently studied in pp interactions at the LHC. The W mass and width definition used here corresponds to a Breit-Wigner with mass-dependent width.
Currently available electroweak data is carefully examined for internal consistency within the Standard Model (SM) framework. Scenarios of excluding/including inconsistent data are explored. An ...objective and plausible approach including all data is proposed in which the SM fit yields M
Higgs = 185
−134
+251 GeV, and the 1σ contour in the M
top vs M
Higgs plane yields an upper limit of 650 GeV for the Higgs mass at 68% confidence level.
Recent results from the LEP collider at CERN are presented: on the identification of e+e− → W+W− and the determination of the W mass and width and limits on its anomalous couplings; the search for ...the Standard Model and non-minimal Higgs; search for SUSY and other new particles. Fits to all electroweak data leading to predictions of the Higgs mass within the Standard Model are presented.
Review of particle physics Hagiwara, K; Nakamura, K; Amsler, C ...
Physical review. D, Particles and fields,
07/2002, Letnik:
66, Številka:
1
Journal Article
Recenzirano
This biennial Review summarizes much of Particle Physics Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles All the particle properties and search limits are listed in Summary Tables We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review) Another new review is on Grand Unified Theories A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review All tables, listings, and reviews (and errata) are also available on the Particle Data Group website http //pdg 1b1 gov.
Abstract A search for new long-lived particles decaying to leptons using proton–proton collision data produced by the CERN LHC at $$\sqrt{s}=13\,\text {Te}\text {V} $$ s = 13 Te is presented. Events ...are selected with two leptons (an electron and a muon, two electrons, or two muons) that both have transverse impact parameter values between 0.01 and 10 $$\,\text {cm}$$ cm and are not required to form a common vertex. Data used for the analysis were collected with the CMS detector in 2016, 2017, and 2018, and correspond to an integrated luminosity of 118 (113) $$\,\text {fb}^{-1}$$ fb - 1 in the $${{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} {{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} $$ e e channel ( $${{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} {\upmu } $$ e μ and $${\upmu } {\upmu } $$ μ μ channels). The search is designed to be sensitive to a wide range of models with displaced $${{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} {\upmu } $$ e μ , $${{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} {{\mathrm{e}}_{\mathrm{}}^{\mathrm{}}} $$ e e , and $${\upmu } {\upmu } $$ μ μ final states. The results constrain several well-motivated models involving new long-lived particles that decay to displaced leptons. For some areas of the available phase space, these are the most stringent constraints to date.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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