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Register a new userProbing New Physics via pp-> W+W- -> lvjj at the CERN LHC
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TeV scale new Physics, e.g., Large Extra Dimensions or Models with anomalous triple vector boson couplings, can lead to excesses in various kinematic regions on the semi-leptonic productions of pp -> WW -> lvjj at the CERN LHC, which, although suffers from large QCD background compared with the pure leptonic channel, can benefit from larger production rates and the reconstructable 4-body mass Mlvjj. We study the search sensitivity through the lvjj channel at the 7TeV LHC on relevant new physics, via probing the hard tails on the reconstructed Mlvjj and the transverse momentum of W-boson (PTW), taking into account main backgrounds and including the parton shower and detector simulation effects. Our results show that with integrated luminosity of 5fb-1, the LHC can already discovery or exclude a large parameter region of the new physics, e.g., 95% CL. limit can be set on the Large Extra Dimensions with a cut-off scale up to 1.5 TeV, and the WWZ anomalous coupling down to, e.g. |lambda_Z|~0.1. Brief results are also given for the 8TeV LHC.
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Triple gauge boson associated production at the LHC serves as an interesting channel to test the robustness of the Standard Model. Any deviation from its SM prediction may indicate possible existence of relevant new physics, e.g., anomalous quartic gauge boson couplings. In this paper, a Monte-Carlo feasibility study of measuring WWA production with pure leptonic decays and probing anomalous quartic gauge-boson (e.g., WWAA) couplings, is presented in detail for the first time, with parton shower and detector simulation effects taken into account. Our results show that at the sqrt{s} = 14 TeV LHC with an integrated luminosity of 100 (30) fb-1, one can reach a significance of 9 (5) sigma to observe the SM WWA production, and can constrain at the 95% CL the anomalous WWAA coupling parameters, e.g., a_{0,c}^W/Lambda^2 (see Ref.[15] for their definitions), at 10^{-5} GeV^{-2}, respectively.
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One of the first channels to be experimentally analyzed at the LHC is $ p + p longrightarrow l^+ + l ^- + X $. A resonance in this channel would be a clear indication of a new gauge neutral boson, as proposed in many extended models. In this paper we call attention to the possibility that the new resonance in this channel could have spin zero. A new high mass spin zero state could be a strong indication of the composite nature of the standard model particles. We have made a comparison between spin zero and spin one for the new hypothetical heavy gauge particle production and decays and we show some distributions that can easily identify their spins.
Precision studies of the production of a high-transverse momentum lepton in association with missing energy at hadron colliders require that electroweak and QCD higher-order contributions are simultaneously taken into account in theoretical predictions and data analysis. Here we present a detailed phenomenological study of the impact of electroweak and strong contributions, as well as of their combination, to all the observables relevant for the various facets of the $psmartpap to {rm lepton} + X$ physics programme at hadron colliders, including luminosity monitoring and Parton Distribution Functions constraint, $W$ precision physics and search for new physics signals. We provide a theoretical recipe to carefully combine electroweak and strong corrections, that are mandatory in view of the challenging experimental accuracy already reached at the Fermilab Tevatron and aimed at the CERN LHC, and discuss the uncertainty inherent the combination. We conclude that the theoretical accuracy of our calculation can be conservatively estimated to be about 2% for standard event selections at the Tevatron and the LHC, and about 5% in the very high $W$ transverse mass/lepton transverse momentum tails. We also provide arguments for a more aggressive error estimate (about 1% and 3%, respectively) and conclude that in order to attain a one per cent accuracy: 1) exact mixed ${cal O}(alpha alpha_s)$ corrections should be computed in addition to the already available NNLO QCD contributions and two-loop electroweak Sudakov logarithms; 2) QCD and electroweak corrections should be coherently included into a single event generator.
An $H^pm W^mp Z$ interaction at the tree level is common feature of new physics models that feature scalar triplets. In this study, we aim to probe the strength of the aforementioned interaction in a model-agnostic fashion at the futuristic 27 TeV proton-proton collider. We assume that the $H^pm$ couples dominantly to ($W^pm,Z$) and ($t,b$). We specifically study the processes that involve the $H^pm W^mp Z$ vertex at the production level, that is, $p p to H^pm j j$ and $p p to Z H^pm$. Moreover, we look into both $H^pm to W^pm Z,~t b$ decays for either production process. Our investigations reveal that the $H^pm j j$ production process has a greater reach compared to $Z H^pm$. Moreover, the discovery potential of a charged Higgs improves markedly with respect to the earlier studies corresponding to lower centre-of-mass energies. Finally, we recast our results in the context of the popular Georgi-Machacek model.
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