scholarly journals Central exclusive production of W boson pairs in pp collisions at the LHC in hadronic and semi-leptonic final states

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
C. Baldenegro ◽  
G. Biagi ◽  
G. Legras ◽  
C. Royon

Abstract We present a phenomenology study on central exclusive production of W+W− boson pairs in proton-proton collisions at the Large Hadron Collider at 14 TeV using the forward proton detectors, such as the ATLAS Forward Proton or the CMS-TOTEM Precision Proton Spectrometer detectors. Final states where at least one of the W bosons decay hadronically in a large-radius jet are considered. The latter extends previous efforts that consider solely leptonic final states. A measurement of exclusive W+W− also allows us to further constrain anomalous quartic gauge boson interactions between photons and W bosons. Expected limits on anomalous quartic gauge couplings $$ {a}_{0,C}^W $$ a 0 , C W associated to dimension-six effective operators are derived for the hadronic, semi-leptonic, and leptonic final states. It is found that the couplings can be probed down to one-dimensional values of $$ {a}_0^W=3.7\times {10}^{-7}{\mathrm{GeV}}^{-2} $$ a 0 W = 3.7 × 10 − 7 GeV − 2 and $$ {a}_C^W=9.2\times {10}^{-7}{\mathrm{GeV}}^{-7} $$ a C W = 9.2 × 10 − 7 GeV − 7 at 95% CL at an integrated luminosity of 300 fb−1 by combining all final states, compared to values of about $$ {a}_0^W=4\times {10}^{-6}{\mathrm{GeV}}^{-2} $$ a 0 W = 4 × 10 − 6 GeV − 2 and $$ {a}_C^W=1\times {10}^{-5}{\mathrm{GeV}}^{-2} $$ a C W = 1 × 10 − 5 GeV − 2 at 95% CL expected for the leptonic channel alone.

2021 ◽  
Author(s):  
Piotr Lebiedowicz ◽  
Josef Leutgeb ◽  
Otto Nachtmann ◽  
Anton Rebhan ◽  
Antoni Szczurek

Author(s):  
V. V. Andreev

In this paper, we obtained the expected constraints on the anomalous CP-even constants of three-boson interactions on the basis of cross-section for the pair production of W+-bosons in proton-proton collisions. The constraints were obtained for luminosity and the kinematic constraints on the final states typical for the CMS experiment at the Large Hadron Collider at =13 s TeV. One-dimensional and two-dimensional regions of constraints for the anomalous parameters of three-boson interactions were calculated. When calculating the cross-section, the usual approximations of small quark masses and values of the CKM matrix elements were not used. The expected values of the anomalous constants are almost an order of magnitude less than the constraints found at the LEP collider at = 200 s GeV in the reaction e–e+ → W–W+.


2014 ◽  
Vol 29 (28) ◽  
pp. 1446011 ◽  
Author(s):  
J. Hollar ◽  

This paper reviews measurements of exclusive production performed by the CMS experiment in proton–proton collisions during Run 1 of the LHC. The results include photon-induced production of μ+μ-, e+e- and W+W- pairs, and a search for strong Central Exclusive Production of γγ pairs.


2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
O. Abdinov ◽  
...  

AbstractMeasurements of $$K_S^0$$KS0 and $$\Lambda ^0$$Λ0 production in $$t\bar{t}$$tt¯ final states have been performed. They are based on a data sample with integrated luminosity of 4.6 $$\mathrm {fb}^{-1}$$fb-1 from proton–proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the ATLAS detector at the Large Hadron Collider. Neutral strange particles are separated into three classes, depending on whether they are contained in a jet, with or without a b-tag, or not associated with a selected jet. The aim is to look for differences in their main kinematic distributions. A comparison of data with several Monte Carlo simulations using different hadronisation and fragmentation schemes, colour reconnection models and different tunes for the underlying event has been made. The production of neutral strange particles in $$t\bar{t}$$tt¯ dileptonic events is found to be well described by current Monte Carlo models for $$K_S^0$$KS0 and $$\Lambda ^0$$Λ0 production within jets, but not for those produced outside jets.


2021 ◽  
Vol 81 (4) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  

AbstractA search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in B meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-$$p_{\mathrm {T}}$$ p T large-radius jet. The full Run 2 dataset is exploited, consisting of $$139~\hbox {fb}^{-1}$$ 139 fb - 1 of data collected from proton–proton collisions at $$\sqrt{s}=13~\mathrm {TeV}$$ s = 13 TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at $$1480~\mathrm {GeV}$$ 1480 GeV and $$1470~\mathrm {GeV}$$ 1470 GeV for the electron and muon channel, respectively.


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