SEARCH FOR NEW PHYSICS IN eμX DATA AT THE TEVATRON USING SLEUTH: A QUASI-MODEL-INDEPENDENT SEARCH STRATEGY FOR NEW PHYSICS

2001 ◽  
Vol 16 (supp01b) ◽  
pp. 888-890
Author(s):  
◽  
BRUCE KNUTESON

We present a quasi-model-independent search for physics beyond the standard model. We define final states to be studied, and construct a rule that identifies a set of variables appropriate for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in the space of those variables and quantifies the significance of any detected excess. After demonstrating the sensititvity of the method, we apply it to the semi-inclusive channel eμX collected in ≈108 pb -1 of [Formula: see text] collisions at [Formula: see text] at the DØ experiment at the Fermilab Tevatron. We find no evidence of new high pT physics in this sample.


2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Yasuhiro Okada ◽  
Luca Panizzi

This work provides an overview on the current status of phenomenology and searches for heavy vector-like quarks, which are predicted in many models of new physics beyond the Standard Model. Searches at Tevatron and at the LHC, here listed and shortly described, have not found any evidence for new heavy fermionic states (either chiral or vector-like) and have therefore posed strong bounds on their masses: depending on specific assumptions on the interactions and on the observed final state, vector-like quarks with masses up to roughly 400–600 GeV have been excluded by all experiments. In order to be as simple and model independent as possible, the chosen framework for the phenomenological analysis is an effective model with the addition of a vector-like quark representation (singlet, doublet, or triplet underSU(2)L) which couples through Yukawa interactions with all SM families. The relevance of different observables for the determination of bounds on mixing parameters is then discussed and a complete overview of possible two body final states for every vector-like quark is provided, including their subsequent decay into SM particles. A list and short description of phenomenological analyses present in the literature are also provided for reference purposes.



2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.



2006 ◽  
Vol 21 (27) ◽  
pp. 5503-5512 ◽  
Author(s):  
M. R. PENNINGTON

Dalitz analyses are introduced as the method for studying hadronic decays. An accurate description of hadron final states is critical not only to an understanding of the strong coupling regime of QCD, but also to the precision extraction of CKM matrix elements. The relation of such final state interactions to scattering processes is discussed.



2015 ◽  
Vol 30 (31) ◽  
pp. 1546009 ◽  
Author(s):  
Konstantinos Kousouris

Jet observables have been exploited extensively during the LHC Run 1 to search for physics beyond the Standard Model. In this article, the most recent results from the ATLAS and CMS collaborations are summarized. Data from proton–proton collisions at 7 and 8 TeV center-of-mass energy have been analyzed to study monojet, dijet, and multijet final states, searching for a variety of new physics signals that include colored resonances, contact interactions, extra dimensions, and supersymmetric particles. The exhaustive searches with jets in Run 1 did not reveal any signal, and the results were used to put stringent exclusion limits on the new physics models.



2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044004
Author(s):  
Tadej Novak

Final states containing both leptons and jets can be used to probe for physics beyond the Standard Model. Searches for new physics models with these signatures, such as heavy neutrinos or leptoquarks, for example, are performed using the ATLAS experiment at the LHC. The results of the most recent searches on 13 TeV [Formula: see text] data will be presented.



2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Xue Gong ◽  
Chong-Xing Yue ◽  
Hai-Mei Yu ◽  
Dong Li

AbstractExistences of vector-like quarks (VLQs) are predicted in many new physics scenarios beyond the Standard Model (SM). We study the possibility of detecting the vector-like bottom quark (VLQ-B) being the SU(2) singlet with electric charge $$-1/3$$ - 1 / 3 at Large Hadron electron Collider (LHeC) in a model-independent framework. The decay properties and single production of VLQ-B at the LHeC are explored. Three types of signatures are investigated. By carrying out a fast simulation for the signals and the corresponding backgrounds, the signal significances are obtained. Our numerical results show that detecting of VLQ-B via the semileptonic channel is better than via the fully hadronic or leptonic channel.



Universe ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 333
Author(s):  
Sergei Chekanov ◽  
Smita Darmora ◽  
Wasikul Islam ◽  
Carlos E. M. Wagner ◽  
Jinlong Zhang

Model-independent searches for physics beyond the Standard Model typically focus on invariant masses of two objects (jets, leptons or photons). In this study, we explore opportunities for similar model-agnostic searches in multi-body invariant masses. In particular, we focus on the situations in which new physics can be observed in a model-independent way in three and four-body invariant masses of jets and leptons. Such searches may have good prospects in finding new physics in the situations when two-body invariant masses, which have been extensively explored at collider experiments in the past, cannot provide sufficient signatures for experimental observations.



2021 ◽  
Vol 136 (9) ◽  
Author(s):  
Jorge de Blas

AbstractWe review the projected sensitivity to physics beyond the Standard Model via indirect searches at the Future$$e+e-$$ e + e - Circular Collider (FCC-ee). The indirect sensitivity to new physics is discussed both from a model-independent perspective, using the formalism of Effective Field Theories, but also from the point of view of more specific classes of well-motivated models.



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