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Related papers: Monolepton production in SMEFT to $\mathcal O(1/\L…

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The persistent anomalies observed in $b \to s\,(\ell^+\ell^-,\,\nu\bar{\nu})$ transitions continue to provide strong motivation for exploring possible extensions of the Standard Model (SM). Motivated by these discrepancies, we present a…

High Energy Physics - Phenomenology · Physics 2026-05-25 Nilakshi Das , Rusa Mandal , Praveen S Patil

Observation of lepton number violation would represent a groundbreaking discovery with profound consequences for fundamental physics and as such, it has motivated an extensive experimental program searching for neutrinoless double beta…

High Energy Physics - Phenomenology · Physics 2024-05-02 Kåre Fridell , Lukáš Gráf , Julia Harz , Chandan Hati

We study constraints on the Standard Model Effective Field Theory (SMEFT) from neutrino oscillations in short-baseline reactor experiments. We calculate the survival probability of reactors antineutrinos at the leading order in the SMEFT…

High Energy Physics - Phenomenology · Physics 2019-06-26 Adam Falkowski , Martín González-Alonso , Zahra Tabrizi

We evaluate the threshold matrix-element for the reaction $pp \to pp\pi^0$ in a fully relativistic Feynman diagrammatic approach. We employ a simple effective range approximation to take care of the S-wave $pp$ final-state interaction. The…

Nuclear Theory · Physics 2009-10-31 V. Bernard , N. Kaiser , Ulf-G. Meißner

In previous works arXiv:2107.12133 and arXiv:2201.05082, we have performed the one-loop matching of both type-I and type-II seesaw models for neutrino masses onto the Standard Model Effective Field Theories (SMEFT). In the present paper, by…

High Energy Physics - Phenomenology · Physics 2023-09-27 Xu Li , Shun Zhou

The cross section for the reaction $e^{-}e^{-} \to \ell^-\ell^-$ ($\ell=\mu,\tau$) is calculated in models with heavy Majorana neutrinos mediating lepton number violating amplitudes at the loop level. The contributing four-point functions…

High Energy Physics - Phenomenology · Physics 2011-09-13 M. Cannoni , St. Kolb , O. Panella

We establish constraints on the dimension-six four-heavy-quark operators in the Standard Model Effective Field Theory (SMEFT) by synthesising LHC measurements of top-quark and single-Higgs production with electroweak precision observables.…

High Energy Physics - Phenomenology · Physics 2025-07-03 Stefano Di Noi , Hesham El Faham , Ramona Gröber , Marco Vitti , Eleni Vryonidou

We investigate how the interference of the SM with ten four-light quark operators in the SMEFT can be constrained thanks to multijet and $Z$, $W$, $\gamma$ VBF production in association with jets. The differential distributions for each…

High Energy Physics - Phenomenology · Physics 2026-05-18 Céline Degrande , Matteo Maltoni

A global analysis of the Standard Model Effective Field Theory (SMEFT) with SFitter is performed using measurements of single top quark production and top quark decay processes from ATLAS and CMS at center-of-mass energies of 7, 8 and 13…

High Energy Physics - Phenomenology · Physics 2019-05-10 Rhea Moutafis

The equations of motion for the Standard Model Effective Field Theory (SMEFT) differ from those in the Standard Model. Corrections due to local contact operators modify the equations of motion and impact matching results at sub-leading…

High Energy Physics - Phenomenology · Physics 2018-12-26 Abdurrahman Barzinji , Michael Trott , Anagha Vasudevan

We demonstrate that the observed baryon asymmetry in the Universe can be accommodated in the extended Standard Model with sequential fourth generation fermions (SM4). We first construct the dimension-6 effective operators of the type…

High Energy Physics - Phenomenology · Physics 2026-05-28 Hsiang-nan Li

Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL Collaboration , G. Abbiendi et al

The production of Z boson pairs in proton-proton (pp) collisions, pp $\to$ (Z/$\gamma^*$)(Z/$\gamma^*$) $\to$ 2$\ell$ 2$\ell'$, where $\ell,\ell'$ = e or $\mu$, is studied at a center-of-mass energy of 13 TeV with the CMS detector at the…

High Energy Physics - Experiment · Physics 2021-03-02 CMS Collaboration

We perform a global analysis of Beauty, Top, $Z$ and Drell-Yan measurements in the framework of the Standard Model effective theory (SMEFT). We work within the minimal flavor violation (MFV) hypothesis, which relates different sectors and…

High Energy Physics - Phenomenology · Physics 2023-11-27 Cornelius Grunwald , Gudrun Hiller , Kevin Kröninger , Lara Nollen

We study the modular symmetric standard-model effective field theory. We employ the stringy Ansatz on coupling structure that 4-point couplings $y^{(4)}$ of matter fields are written by a product of 3-point couplings $y^{(3)}$ of matter…

High Energy Physics - Phenomenology · Physics 2022-04-06 Tatsuo Kobayashi , Hajime Otsuka , Morimitsu Tanimoto , Kei Yamamoto

In this work we consider the Standard Model Effective Field Theory extended with right-handed neutrinos, the $\nu$SMEFT, and calculate the full set of one-loop anomalous dimensions that are proportional to Yukawa couplings. These…

High Energy Physics - Phenomenology · Physics 2024-08-06 Marco Ardu , Xabier Marcano

In view of the forthcoming experiments at high energy $e^+ e^-$ colliders, LEP2 and beyond, the process $e^+ e^- \to W^+ W^- \to 4f$ has been investigated for {\it off-shell} $W$'s. After deriving the matrix element for the process within…

High Energy Physics - Phenomenology · Physics 2009-10-28 G. Montagna , O. Nicrosini , G. Passarino , F. Piccinini

A study of the order $\alpha_s^2$ corrections to the Drell Yan (non-singlet) cross section for incoming states of arbitrary longitudinal helicities is presented. The study is performed in the case of the transverse momentum distributions,…

High Energy Physics - Phenomenology · Physics 2014-11-17 Sanghyeon Chang , Claudio Coriano , R. D. Field , L. E. Gordon

We obtain the complete operator bases at mass dimensions 5, 6, 7, 8, 9 for the low energy effective field theory (LEFT), which parametrize various physics effects between the QCD scale and the electroweak scale. The independence of the…

High Energy Physics - Phenomenology · Physics 2021-07-07 Hao-Lin Li , Zhe Ren , Ming-Lei Xiao , Jiang-Hao Yu , Yu-Hui Zheng

Cross-sections and angular distributions for hadronic and lepton pair final states in e+e- collisions at a centre-of-mass energy near 189 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the…

High Energy Physics - Experiment · Physics 2008-11-26 The OPAL Collaboration , G. Abbiendi