scholarly journals VBS W±W±H production at the HL-LHC and a 100 TeV pp-collider

2017 ◽  
Vol 32 (18) ◽  
pp. 1750106 ◽  
Author(s):  
Christoph Englert ◽  
Qiang Li ◽  
Michael Spannowsky ◽  
Mengmeng Wang ◽  
Lei Wang
Keyword(s):  
Direct Evidence ◽  
Vector Boson ◽  
Monte Carlo Study ◽  
New Physics ◽  
Hadron Colliders ◽  
Text Production ◽  
Truncation Scheme ◽  
Charged Leptons ◽  
Vector Boson Scattering ◽  
The Impact

[Formula: see text] production at hadron colliders through vector boson scattering is a so far unconsidered process, which leads to a clean signature of two same-sign charged leptons and two widely separated jets. This process is sensitive to the [Formula: see text] and [Formula: see text] couplings and any deviation of these couplings from their SM predictions serves as direct evidence of new physics beyond the SM. In this paper, we perform a Monte Carlo study of this process for the [Formula: see text] LHC and a 100 TeV [Formula: see text]-collider, and provide projections of the constraints on the triple-Higgs and [Formula: see text] quartic couplings for these environments. In particular, we consider the impact of pileup on the expected sensitivity in this channel. Our analysis demonstrates that although the sensitivity to the [Formula: see text] coupling is rather low, the [Formula: see text] coupling can be constrained in this channel within [Formula: see text][Formula: see text]100% and [Formula: see text][Formula: see text]20% at 95% confidence level around the SM prediction at the HL-LHC and a 100 TeV [Formula: see text]-collider, respectively. We have also provided results with simple truncation scheme, in consideration of unitarity safety.

scholarly journals Observation and measurements of vector-boson scattering with the ATLAS detector

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044002
Author(s):  
Ondřej Penc
Keyword(s):  
Cross Sections ◽  
Vector Boson ◽  
Center Of Mass ◽  
New Physics ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Number Of Generators ◽  
Text Production ◽  
Vector Boson Scattering ◽  
Electroweak Boson

The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous quartic gauge couplings. In this paper, we present recent results on vector-boson scattering from the ATLAS experiment using proton–proton collisions with a center-of-mass energy of 13 TeV at the LHC. This includes the observation of [Formula: see text], [Formula: see text], and same-sign [Formula: see text] production via vector-boson scattering along with a measurement of [Formula: see text] production ([Formula: see text] denotes [Formula: see text] or [Formula: see text] boson) in semileptonic final states. The results can be used to constrain new physics that manifests as anomalous electroweak-boson self-interactions. Finally, predicted cross-sections for the electroweak scattering of two same-sign [Formula: see text] bosons in association with two jets are compared for a number of generators.

scholarly journals New Physics/Resonances in Vector Boson Scattering at the LHC

2016 ◽  
Author(s):  
Jürgen Reuter ◽  
Wolfgang Kilian ◽  
Thorsten Ohl ◽  
Marco Sekulla
Keyword(s):  
Vector Boson ◽  
New Physics ◽  
Vector Boson Scattering

scholarly journals Study of Vector Boson Scattering and Search for New Physics in Events with Two Same-Sign Leptons and Two Jets

2015 ◽  
Vol 114 (5) ◽  
Author(s):  
V. Khachatryan ◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Vector Boson ◽  
New Physics ◽  
Vector Boson Scattering ◽  
Two Jets

scholarly journals Exploring QED Effects to Diphoton Production at Hadron Colliders

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 994
Author(s):  
Leandro Cieri ◽  
German Sborlini
Keyword(s):  
Invariant Mass Distribution ◽  
Percent Level ◽  
New Physics ◽  
Hadron Colliders ◽  
Subtraction Method ◽  
Experimental Conditions ◽  
Event Reconstruction ◽  
Phenomenological Studies ◽  
Qed Effects ◽  
The Impact

In this article, we report phenomenological studies about the impact of O(α) corrections to diphoton production at hadron colliders. We explore the application of the Abelianized version of the qT-subtraction method to efficiently compute NLO QED contributions, taking advantage of the symmetries relating QCD and QED corrections. We analyze the experimental consequences due to the selection criteria and we find percent-level deviations for Mγγ>1TeV. An accurate description of the tail of the invariant mass distribution is very important for new physics searches which have the diphoton process as one of their main backgrounds. Moreover, we emphasize the importance of properly dealing with the observable photons by reproducing the experimental conditions applied to the event reconstruction.

scholarly journals The upgraded ATLAS detector for the search of new physics with diboson final states

2020 ◽  
Author(s):  
Δέσποινα Σαμψωνίδου
Keyword(s):  
Monte Carlo ◽  
Vector Boson ◽  
New Physics ◽  
Atlas Detector ◽  
Final States ◽  
Hadron Spectrum ◽  
Quark Confinement ◽  
Vector Boson Scattering

Η παρούσα διδακτορική διατριβή επικεντρώνεται στη μελέτη παραγωγής γεγονότων W ± Z από συγκρούσεις πρωτονίων στο Μεγάλο Επιταχυντή Αδρονίων (LHC), και την ταυτόχρονη σκέδαση δυο μποζονίων βαθμίδας W, Z από τα αρχικά κουάρκ των πρωτονίων στις συγκρούσεις του LHC (Vector Boson Scattering). Τα γεγονότα που αναλύθηκαν καταγράφτηκαν από το πείραμα ATLAS και αντιστοιχούν σε ολοκληρωμένη φωτεινότητα 36.1 fb−1 σε ενέργεια κέντρου μάζας 13 TeV. Επιλέγονται τα γεγονότα στα οποία τα W±Z διασπώνται σε ηλεκτρόνια και μιόνια. Ένα μέρος της διατριβής αφορά στη μελέτη της απόδοσης της ανακατασκευής των μιονίων στην εμπρόσθια περιοχή. Η μελέτη αυτή έγινε στα πλαίσια της απόκτησης του τίτλου του ”συγγραφέα” στο πείραμα ΑΤΛΑΣ, και αποτελεί σημαντική συνεισφορά στο Πείραμα, καθότι δίνει την δυνατότητα να χρησιμοποιηθούν τα μιόνια της εμπρόσθιας περιοχής του ανιχνευτή και επομένως αυξάνει την διαθέσιμη στατιστική, ιδιαίτερα για αναλύσεις που αναζητούν σπάνια γεγονότα που περιλαμβάνουν και μιόνια. Τα γεγονότα W ± Z πρέπει να έχουν τρία καλώς απομονωμένα λεπτόνια και ελλείπουσα ενέργεια. Η κυρίαρχη πηγή υποβάθρου είναι τα γεγονότα που προέρχονται από διαδικασίες ZZ, Z + jets, ttbar. Οι συνεισφορές υποβάθρου από διαδικασίες ΖΖ υπολογίζονται χρησιμοποιώντας γεγονότα προσομοίωσης από Monte Carlo. Το υπόβαθρο όμως που προέρχεται από τη διαδικασία Z + jets καθώς επίσης και από την παραγωγή του ttbar quark εκτιμάται χρησιμοποιώντας τα δεδομένα του AT LAS , επειδή οι προσομοιώσεις δεν περιγράφουν με ακρίβεια τις συγκεκριμένες διασπάσεις. Η ενεργός διατομή για για καθένα από τα τέσσερα λεπτονικά κανάλια που εξετάστηκαν μετρήθηκε σfid= 63.7 ± 1.0(stat.) ± 2.3(syst.) ± 1.4(lumi.)fb. Τα γεγονότα W Z από σκέδαση μποζονίων βαθμίδας επιλέγονται από την προηγούμενη κατηγορία WZ, αν περιέχουν δυο πiδακες σωματιδίων σε αντίθετα χωρικά ημισφαίρια και αναλοίωτη μάζα του ζεύγους μεγαλύτερη από 500GeV . Η κυρίαρχη πηγή υποβάθρου είναι τα γεγονότα που προέρχονται από διαδικασίες W Zjj − QCD, ttV και ZZjj. Οι συνεισφορά στο υπόβαθρο από τις παραπάνω διαδικασίες υπολογίζονται χρησιμοποιώντας γεγονότα προσομοίωσης από Monte Carlo και δεδομένα του ATLAS. Η ενεργός διατομή για ένα λεπτονικό κανάλι διάσπασης μετρήθηκε σEW (W ±Zjj → lνlljj) = 0.57 ±0.14 −0.13(stat.) ±0.05 (sys.)0.04 (th.)fb. Επιπλέον, πιθανά αποτελέσματα φυσικής πέρα απο το −0.04 −0.03 καθιερωμένο πρότυπο αναζητήθηκαν στα κανάλια λεπτονικών διασπάσεων WZ και WZVBS μέσω των τελεστών Ενεργών Θεωριών Πεδίου, με διαστάσεις 6 και 8. Η ευαισθησία όλων των πιθανών τελεστών μελετήθηκε με χρήση προσομοιώσεων MonteCarlo. Η μελέτη της απόδοσης της ανακατασκευής των μιονίων στην εμπρόσθια περιοχή παρουσιάστηκε στα συνέδρια ICNFP 2016 και XIIth quark confinement and the Hadron spectrum. Η μέτρηση του λεπτονικού καναλιού WZ VBS εκδόθηκε στο Physics Letters B,Volume 793 και παρουσιάστηκε στο συνέδριο Lepton-Photon 2019. Οι μελέτες σχετικά με τις Ενεργές Θεωρίες Πεδίου παρουσιάστηκαν στα συνέδρια Multi-Boson Interactions 2019 και HEP 2019.

scholarly journals Impact of additional bosons on the exploration of the Higgs boson at the LHC

2017 ◽  
Vol 32 (34) ◽  
pp. 1746010 ◽  
Author(s):  
Yaquan Fang ◽  
Mukesh Kumar ◽  
Bruce Mellado ◽  
Yu Zhang ◽  
Maosen Zhu
Keyword(s):  
Higgs Boson ◽  
Production Cross ◽  
Vector Boson ◽  
New Production ◽  
Final State ◽  
Proton Proton ◽  
Text Production ◽  
Proton Data ◽  
Inclusive Rate ◽  
The Impact

The LHC is making strides in the exploration of the properties of the newly discovered Higgs boson, [Formula: see text]. In Refs. 7–9 the compatibility of the proton–proton data reported in the Run I period with the presence of a heavy scalar, [Formula: see text], with a mass around 270 GeV and its implications were explored. This boson would decay predominantly to [Formula: see text], where [Formula: see text], is a lighter scalar boson. The production cross-section of [Formula: see text] is considerable and it would significantly affect the inclusive rate of [Formula: see text]. The contamination from this new production mechanism would depend strongly on the final state used to measure the rate of [Formula: see text]. The contamination in the rate measurement of [Formula: see text], [Formula: see text], [Formula: see text] is estimated to be small. This statement does not depend strongly on assumptions made on the decay of [Formula: see text]. The impact on other channels related to the search of Vector Boson Fusion and [Formula: see text] production with the diphoton decay is evaluated, where the dependence on assumption on the decay of [Formula: see text] is expected to be significant.

scholarly journals Extract the energy scale of anomalous γγ → W+W− scattering in the vector boson scattering process using artificial neural networks

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Ji-Chong Yang ◽  
Jin-Hua Chen ◽  
Yu-Chen Guo
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Vector Boson ◽  
Hadron Collider ◽  
New Physics ◽  
Suppressive Effect ◽  
Effective Field ◽  
Energy Scale ◽  
Artificial Neural ◽  
Vector Boson Scattering

Abstract As a model independent approach to search for the signals of new physics (NP) beyond the Standard Model (SM), the SM effective field theory (SMEFT) draws a lot of attention recently. The energy scale of a process is an important parameter in the study of an EFT such as the SMEFT. However, for the processes at a hadron collider with neutrinos in the final states, the energy scales are difficult to reconstruct. In this paper, we study the energy scale of anomalous γγ → W+W− scattering in the vector boson scattering (VBS) process pp → jjℓ+ℓ−ν$$ \overline{\nu} $$ ν ¯ at the large hadron collider (LHC) using artificial neural networks (ANNs). We find that the ANN is a powerful tool to reconstruct the energy scale of γγ → W+W− scattering. The factors affecting the effects of ANNs are also studied. In addition, we make an attempt to interpret the ANN and arrive at an approximate formula which has only five fitting parameters and works much better than the approximation derived from kinematic analysis. With the help of ANN approach, the unitarity bound is applied as a cut on the energy scale of γγ → W+W− scattering, which is found to has a significant suppressive effect on signal events. The sensitivity of the process pp → jjℓ+ℓ−ν$$ \overline{\nu} $$ ν ¯ to anomalous γγWW couplings and the expected constraints on the coefficients at current and possible future LHC are also studied.

scholarly journals Vector-Boson scattering at the LHC: Unraveling the electroweak sector

2021 ◽  
pp. 2130009
Author(s):  
Roberto Covarelli ◽  
Mathieu Pellen ◽  
Marco Zaro
Keyword(s):  
Vector Boson ◽  
Hadron Collider ◽  
New Physics ◽  
Theoretical Description ◽  
Point Of View ◽  
Experimental Point ◽  
Gauge Sector ◽  
Signal Sensitivity ◽  
Electroweak Sector ◽  
Vector Boson Scattering

Vector-boson scattering (VBS) processes probe the innermost structure of electroweak (EW) interactions in the Standard Model (SM), and provide a unique sensitivity for new physics phenomena affecting the gauge sector. In this review, we report on the salient aspects of this class of processes, both from the theory and experimental point of view. We start by discussing recent achievements relevant for their theoretical description, some of which have set important milestones in improving the precision and accuracy of the corresponding simulations. We continue by covering the development of experimental techniques aimed at detecting these rare processes and improving the signal sensitivity over large backgrounds. We then summarize the details of the most relevant VBS signatures and review the related measurements available to date, along with their comparison with SM predictions. We conclude by discussing the perspective at the upcoming Large Hadron Collider runs and at future hadron facilities.

scholarly journals The Physics Case for an Electron-Muon Collider

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Meng Lu ◽  
Andrew Michael Levin ◽  
Congqiao Li ◽  
Antonios Agapitos ◽  
Qiang Li ◽  
...  
Keyword(s):  
Charged Lepton ◽  
Vector Boson ◽  
New Physics ◽  
Muon Beam ◽  
Lepton Flavor Violation ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Muon Collider ◽  
200 Gev ◽  
Vector Boson Scattering

An electron-muon collider with an asymmetric collision profile targeting multi-ab-1 integrated luminosity is proposed. This novel collider, operating at collision energies of, e.g., 20–200 GeV, 50–1000 GeV, and 100–3000 GeV, would be able to probe charged lepton flavor violation and measure Higgs boson properties precisely. The collision of an electron and muon beam leads to less physics background compared with either an electron-electron or a muon-muon collider, since electron-muon interactions proceed mostly through higher-order vector boson fusion and vector boson scattering processes. The asymmetric collision profile results in collision products that are boosted towards the electron beam side, which can be exploited to reduce beam-induced background from the muon beam to a large extent. With this in mind, one can imagine a lepton collider complex, starting from colliding order 10 GeV electron and muon beams for the first time in history and to probe charged lepton flavor violation, then to be upgraded to a collider with 50-100 GeV electron and 1-3 TeV muon beams to measure Higgs properties and search for new physics and finally to be transformed to a TeV-scale muon-muon collider. The cost should vary from order 100 million to a few billion dollars, corresponding to different stages, which make the funding situation more practical.

scholarly journals Global analysis of the Sivers functions at NLO+NNLL in QCD

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Miguel G. Echevarria ◽  
Zhong-Bo Kang ◽  
John Terry
Keyword(s):  
Pair Production ◽  
Global Analysis ◽  
Vector Boson ◽  
Lepton Pair ◽  
Transverse Spin ◽  
Dglap Evolution ◽  
Spin Asymmetries ◽  
Lepton Pair Production ◽  
Asymmetry Data ◽  
The Impact

Abstract We perform global fit to the quark Sivers function within the transverse momentum dependent (TMD) factorization formalism in QCD. We simultaneously fit Sivers asymmetry data from Semi-Inclusive Deep Inelastic Scattering (SIDIS) at COMPASS, HERMES, and JLab, from Drell-Yan lepton pair production at COMPASS, and from W/Z boson at RHIC. This extraction is performed at next-to-leading order (NLO) and next-to-next-to leading logarithmic (NNLL) accuracy. We find excellent agreement between our extracted asymmetry and the experimental data for SIDIS and Drell-Yan lepton pair production, while tension arises when trying to describe the spin asymmetries of W/Z bosons at RHIC. We carefully assess the situation, and we study in details the impact of the RHIC data and their implications through different ways of performing the fit. In addition, we find that the quality of the description of W/Z vector boson asymmetry data could be strongly sensitive to the DGLAP evolution of Qiu-Sterman function, besides the usual TMD evolution. We present discussion on this and the implications for measurements of the transverse-spin asymmetries at the future Electron Ion Collider.

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