STRONGLY INTERACTING W BOSONS AT e-e- COLLIDERS

2000 ◽  
Vol 15 (16) ◽  
pp. 2387-2396
Author(s):  
WOLFGANG KILIAN

If no Higgs boson exists, scattering amplitudes of massive vector bosons become strong at TeV energies. Below the threshold where new resonances appear, they are described by an effective chiral Lagrangian, which introduces a small number of new universal parameters at each order of a low-energy expansion. These parameters can be measured in (quasi-)elastic scattering processes of massive vector bosons in e-e± collisions. Analyzing processes such as e-e-→νeνeW-W-, a sensitivity of the order 10-2 can be reached at a high-luminosity 1 TeV linear collider.

2018 ◽  
Vol 192 ◽  
pp. 00032 ◽  
Author(s):  
Rosamaria Venditti

The High-Luminosity Large Hadron Collider (HL-LHC) is a major upgrade of the LHC, expected to deliver an integrated luminosity of up to 3000/fb over one decade. The very high instantaneous luminosity will lead to about 200 proton-proton collisions per bunch crossing (pileup) superimposed to each event of interest, therefore providing extremely challenging experimental conditions. The scientific goals of the HL-LHC physics program include precise measurement of the properties of the recently discovered standard model Higgs boson and searches for beyond the standard model physics (heavy vector bosons, SUSY, dark matter and exotic long-lived signatures, to name a few). In this contribution we will present the strategy of the CMS experiment to investigate the feasibility of such search and quantify the increase of sensitivity in the HL-LHC scenario.


2000 ◽  
Vol 15 (16) ◽  
pp. 2455-2460
Author(s):  
PAUL H. FRAMPTON

Theoretical background for bileptonic gauge bosons is reviewed — both the SU(15) GUT model and the 3-3-1 model. Mass limits on bileptons are discussed coming from e+e- scattering, polarized muon decay and muonium–antimuonium conversion. Discovery in e-e- at a linear collider at low energy (100 GeV) and high luminosity (1033/cm2/s) is emphasized.


2000 ◽  
Vol 15 (16) ◽  
pp. 2543-2554 ◽  
Author(s):  
J. E. SPENCER

Effects that limit the luminosities of a general purpose linear collider (GLC) capable of [Formula: see text] and [Formula: see text] channels are discussed together with mitigations. Previous results are extended to understand the differences between channels to maximize the generalized luminosity. A standard NLC configuration at [Formula: see text] is used for comparison. Without charge compensation or bunch shaping, such flat beam configurations (aspect ratios R*≫1) imply major disadvantages for e-e- due to the strong disruption (D) and small, longitudinal f-numbers [Formula: see text] that are imposed. Previous round and flat beam configurations are studied as functions of D (or fb#), fl# and the constraints ΔB, Nγ and ϒ. Round beams with decreased disruptions and larger fl-stops are preferred with tensor beams, charge compensation or other bunch manipulation schemes. A low energy, high luminosity prototype is again proposed based on the possible physics.


2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Henning Bahl ◽  
Philip Bechtle ◽  
Sven Heinemeyer ◽  
Judith Katzy ◽  
Tobias Klingl ◽  
...  

Abstract The $$ \mathcal{CP} $$ CP structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this study, all relevant inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments are used to constrain the $$ \mathcal{CP} $$ CP -nature of the top-Yukawa interaction. The model dependence of the constraints is studied by successively allowing for new physics contributions to the couplings of the Higgs boson to massive vector bosons, to photons, and to gluons. In the most general case, we find that the current data still permits a significant $$ \mathcal{CP} $$ CP -odd component in the top-Yukawa coupling. Furthermore, we explore the prospects to further constrain the $$ \mathcal{CP} $$ CP properties of this coupling with future LHC data by determining tH production rates independently from possible accompanying variations of the $$ t\overline{t}H $$ t t ¯ H rate. This is achieved via a careful selection of discriminating observables. At the HL-LHC, we find that evidence for tH production at the Standard Model rate can be achieved in the Higgs to diphoton decay channel alone.


2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
John Terning ◽  
Christopher B. Verhaaren

Abstract Theories with both electric and magnetic charges (“mutually non-local” theories) have several major obstacles to calculating scattering amplitudes. Even when the interaction arises through the kinetic mixing of two, otherwise independent, U(1)’s, so that all low-energy interactions are perturbative, difficulties remain: using a self-dual, local formalism leads to spurious poles at any finite order in perturbation theory. Correct calculations must show how the spurious poles cancel in observable scattering amplitudes. Consistency requires that one type of charge is confined as a result of one of the U(1)’s being broken. Here we show how the constraints of confinement and parity conservation on observable processes manages to cancel the spurious poles in scattering and pair production amplitudes, paving the way for systematic studies of the experimental signatures of “dark” electric-magnetic processes. Along the way we demonstrate some novel effects in electric-magnetic interactions, including that the amplitude for single photon production of magnetic particles by electric particles vanishes.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Gavin K. C. Cheung ◽  
◽  
Christopher E. Thomas ◽  
David J. Wilson ◽  
Graham Moir ◽  
...  

Abstract Elastic scattering amplitudes for I = 0 DK and I = 0, 1 $$ D\overline{K} $$ D K ¯ are computed in S, P and D partial waves using lattice QCD with light-quark masses corresponding to mπ = 239 MeV and mπ = 391 MeV. The S-waves contain interesting features including a near-threshold JP = 0+ bound state in I = 0 DK, corresponding to the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ (2317), with an effect that is clearly visible above threshold, and suggestions of a 0+ virtual bound state in I = 0 $$ D\overline{K} $$ D K ¯ . The S-wave I = 1 $$ D\overline{K} $$ D K ¯ amplitude is found to be weakly repulsive. The computed finite-volume spectra also contain a deeply-bound D* vector resonance, but negligibly small P -wave DK interactions are observed in the energy region considered; the P and D-wave $$ D\overline{K} $$ D K ¯ amplitudes are also small. There is some evidence of 1+ and 2+ resonances in I = 0 DK at higher energies.


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