scholarly journals On the Interpretation of Nonresonant Phenomena at Colliders

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Miguel G. Folgado ◽  
Veronica Sanz

With null results in resonance searches at the LHC, the physics potential focus is now shifting towards the interpretation of nonresonant phenomena. An example of such shift is the increased popularity of the EFT programme. We can embark on such programme owing to the good integrated luminosity and an excellent understanding of the detectors, which will allow these searches to become more intense as the LHC continues. In this paper, we provide a framework to perform this interpretation in terms of a diverse set of scenarios, including (1) generic heavy new physics described at low energies in terms of a derivative expansion, such as in the EFT approach; (2) very light particles with derivative couplings, such as axions or other light pseudo-Goldstone bosons; and (3) the effect of a quasicontinuum of resonances, which can come from a number of strongly coupled theories, extradimensional models, clockwork set-ups, and their deconstructed cousins. These scenarios are not equivalent despite all nonresonance, although the matching among some of them is possible, and we provide it in this paper.

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Angloher ◽  
F. Ardellier-Desages ◽  
A. Bento ◽  
L. Canonica ◽  
A. Erhart ◽  
...  

AbstractCoherent elastic neutrino–nucleus scattering ($$\hbox {CE}\nu \hbox {NS}$$CEνNS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model. Nuclear reactors are promising sources to explore this process at low energies since they deliver large fluxes of anti-neutrinos with typical energies of a few MeV. In this paper, a new-generation experiment to study $$\hbox {CE}\nu \hbox {NS}$$CEνNS is described. The NUCLEUS experiment will use cryogenic detectors which feature an unprecedentedly low-energy threshold and a time response fast enough to be operated under above-ground conditions. Both sensitivity to low-energy nuclear recoils and a high event rate tolerance are stringent requirements to measuring $$\hbox {CE}\nu \hbox {NS}$$CEνNS of reactor anti-neutrinos. A new experimental site, the Very-Near-Site (VNS), at the Chooz nuclear power plant in France is described. The VNS is located between the two 4.25 $$\hbox {GW}_{\mathrm {th}}$$GWth reactor cores and matches the requirements of NUCLEUS. First results of on-site measurements of neutron and muon backgrounds, the expected dominant background contributions, are given. In this paper a preliminary experimental set-up with dedicated active and passive background reduction techniques and first background estimations are presented. Furthermore, the feasibility to operate the detectors in coincidence with an active muon veto at shallow overburden is studied. The paper concludes with a sensitivity study pointing out the physics potential of NUCLEUS at the Chooz nuclear power plant.


2016 ◽  
Vol 31 (22) ◽  
pp. 1643004 ◽  
Author(s):  
Graham D. Kribs ◽  
Ethan T. Neil

We review models of new physics in which dark matter arises as a composite bound state from a confining strongly-coupled non-Abelian gauge theory. We discuss several qualitatively distinct classes of composite candidates, including dark mesons, dark baryons, and dark glueballs. We highlight some of the promising strategies for direct detection, especially through dark moments, using the symmetries and properties of the composite description to identify the operators that dominate the interactions of dark matter with matter, as well as dark matter self-interactions. We briefly discuss the implications of these theories at colliders, especially the (potentially novel) phenomenology of dark mesons in various regimes of the models. Throughout the review, we highlight the use of lattice calculations in the study of these strongly-coupled theories, to obtain precise quantitative predictions and new insights into the dynamics.


2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Koushik Ganesan ◽  
Andrew Lucas

Abstract We initiate a study of finite temperature transport in gapless and strongly coupled quantum theories with charge and dipole conservation using gauge-gravity duality. In a model with non-dynamical gravity, the bulk fields of our model include a suitable mixed-rank tensor which encodes the boundary multipole symmetry. We describe how such a theory can arise at low energies in a theory with a covariant bulk action. Studying response functions at zero density, we find that charge relaxes via a fourth-order subdiffusion equation, consistent with a recently-developed field-theoretic framework.


1996 ◽  
Vol 11 (18) ◽  
pp. 3195-3225 ◽  
Author(s):  
M. SHIFMAN

The values of αs determined from low and high energy measurements are in irreconcilable contradiction with each other. The current status of the problem is critically reviewed. Consequences of the αs contradiction, in conjunction with other anomalies detected at the Z peak, are discussed. This article has been updated in accordance with experimental numbers reported at summer conferences.


2016 ◽  
Vol 31 (33) ◽  
pp. 1644005 ◽  
Author(s):  
Zhen Liu

I summarize our recent works on using differential observables to explore the physics potential of future [Formula: see text] colliders in the framework of Higgs effective field theory. This proceeding is based upon Refs. 1 and 2. We study angular observables in the [Formula: see text] channel at future circular [Formula: see text] colliders such as CEPC and FCC-ee. Taking into account the impact of realistic cut acceptance and detector effects, we forecast the precision of six angular asymmetries at CEPC (FCC-ee) with center-of-mass energy [Formula: see text] GeV and 5 (30) ab[Formula: see text] integrated luminosity. We then determine the projected sensitivity to a range of operators relevant for the Higgsstrahlung process in the dimension-6 Higgs EFT. Our results show that angular observables provide complementary sensitivity to rate measurements when constraining various tensor structures arising from new physics. We further find that angular asymmetries provide a novel means of constraining the “blind spot” in indirect limits on supersymmetric scalar top partners. We also discuss the possibility of using [Formula: see text]-fusion at [Formula: see text] machines at different energies to probe new operators.


2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Xi-Yan Tian ◽  
Liu-Feng Du ◽  
Yao-Bei Liu

AbstractThe vectorlike top partners are potential signature of some new physics beyond the Standard Model at the TeV scale. In this paper, we propose to search for the vectorlike T quark with charge 2/3 in the framework of a simplified model where the top partners only couples with the third generation of Standard Model quarks. We investigate the observability for electroweak production of a vectorlike T quark in association with a standard model bottom quark through the process $$pp \rightarrow T\bar{b}j$$ p p → T b ¯ j with the subsequent decay mode of $$T\rightarrow t(\rightarrow b W^+\rightarrow b \ell ^{+} \nu _{\ell })h( \rightarrow \gamma \gamma )$$ T → t ( → b W + → b ℓ + ν ℓ ) h ( → γ γ ) , at the proposed High Energy Large Hadron Collider (HE-LHC) and Future Circular Collider in hadron-hadron mode (FCC-hh) including the realistic detector effects. The 95% confidence level excluded regions and the $$5\sigma $$ 5 σ discovery reach in the parameter plane of $$\kappa _{T}-m_T$$ κ T - m T , are respectively obtained at the HE-LHC with the integrated luminosity of 15 ab$$^{-1}$$ - 1 and the FCC-hh with the integrated luminosity of 30 ab$$^{-1}$$ - 1 . We also analyze the projected sensitivity in terms of the production cross section times branching fraction at the HE-LHC and FCC-hh.


2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Lorenzo Calibbi ◽  
M. L. López-Ibáñez ◽  
Aurora Melis ◽  
Oscar Vives

AbstractThe confirmation of the discrepancy with the Standard Model predictions in the anomalous magnetic moment by the Muon g-2 experiment at Fermilab points to a low scale of new physics. Flavour symmetries broken at low energies can account for this discrepancy but these models are much more restricted, as they would also generate off-diagonal entries in the dipole moment matrix. Therefore, if we assume that the observed discrepancy in the muon $$g-2$$ g - 2 is explained by the contributions of a low-energy flavor symmetry, lepton flavour violating processes can constrain the structure of the lepton mass matrices and therefore the flavour symmetries themselves predicting these structures. We apply these ideas to several discrete flavour symmetries popular in the leptonic sector, such as $$\Delta (27)$$ Δ ( 27 ) , $$A_4$$ A 4 , and $$A_5 < imes \mathrm{CP}$$ A 5 ⋉ CP .


2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Qiurong Mou ◽  
Sibo Zheng

A hypothetical scalar mixed with the standard model Higgs appears in few contexts of new physics. This study addresses the question what mass range is in the reach of 14 TeV LHC given different magnitudes of mixing angle α, where event simulations are based on production from vector-boson fusion channel and decays into SM leptons through WW or ZZ. It indicates that heavy scalar mass up to 539 GeV and 937 GeV can be excluded by integrated luminosity of 300 fb-1 and 3000 fb-1, respectively, for sin2α larger than 0.04.


2016 ◽  
Vol 31 (33) ◽  
pp. 1644003 ◽  
Author(s):  
Matthew Reece

I give an overview of the physics potential at possible future [Formula: see text] colliders, including the ILC, FCC-ee, and CEPC. The goal is to explain some of the measurements that can be done in the context of electroweak precision tests and Higgs couplings, to compare some of the options under consideration, and to put the measurements in context by summarizing their implications for some new physics scenarios. This is a writeup of a plenary talk at the Hong Kong University of Science and Technology Jockey Club Institute for Advanced Study Program on High Energy Physics Conference, 18–21 January 2016. Some previously unpublished electroweak precision results for FCC-ee and CEPC are included.


2012 ◽  
Vol 27 (30) ◽  
pp. 1230031
Author(s):  
◽  
PIERLUIGI CAMPANA ◽  
GAIA LANFRANCHI

We present a review of the operation and of the most recent results from the LHCb experiment at the LHC collider, based on the analyses performed using the data collected in 2010 and 2011, which correspond to an integrated luminosity of ~ 1 fb-1. These measurements set stringent new limits on the contributions of New Physics processes in the field of rare b decays, and in the search for CP violation in B0 and [Formula: see text] mesons decays. In addition, a summary of results from studies of CP violation in the charm sector are presented, together with measurements in quarkonia production, in spectroscopy, in electroweak physics and in searches for exotica. The planned upgrade of LHCb is also briefly discussed.


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