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We investigate solutions to the flavour anomalies in $B$ decays based on loop diagrams of a "split" dark sector characterised by the simultaneous presence of heavy particles at the TeV scale and light particles around and below the…

High Energy Physics - Phenomenology · Physics 2020-09-01 Luc Darmé , Marco Fedele , Kamila Kowalska , Enrico Maria Sessolo

The anomalies in the $B$-meson sector, in particular $R_{K^{(*)}}$ and $R_{D^{(*)}}$, are often interpreted as hints for physics beyond the Standard Model. To this end, leptoquarks or a heavy $Z'$ represent the most popular SM extensions…

High Energy Physics - Phenomenology · Physics 2021-01-07 Thomas Faber , Matěj Hudec , Michal Malinský , Peter Meinzinger , Werner Porod , Florian Staub

Several experiments revealed intriguing hints for lepton flavor universality (LFU) violating new physics (NP) in semi-leptonic $B$ meson decays, mainly in $b \to c \tau \nu$ and $b \to s \ell^+ \ell^-$ transitions at the $3-5\,\sigma$…

High Energy Physics - Phenomenology · Physics 2019-06-05 Andreas Crivellin , Francesco Saturnino

We present a minimal framework of $U(1)_{B-L}$ gauge extension of the Standard Model explaining dark matter abundance and matter-antimatter asymmetry simultaneously through an attractive mechanism of TeV scale WIMPy leptogenesis, testable…

High Energy Physics - Phenomenology · Physics 2016-05-05 Arnab Dasgupta , Chandan Hati , Sudhanwa Patra , Utpal Sarkar

We study a generic leptophilic $U(1)_X$ extension of the standard model with a light gauge boson. The $U(1)_X$ charge assignments for the leptons are guided by lepton universality violating (LUV) observables in semileptonic $b \to…

High Energy Physics - Phenomenology · Physics 2020-12-30 Debasish Borah , Lopamudra Mukherjee , Soumitra Nandi

Recent measurements in $B \to K^{(*)} \mu^+ \mu^-$ decays are somewhat discrepant with Standard Model predictions. They may be harbingers of new physics at an energy scale potentially accessible to direct discovery. We estimate the…

High Energy Physics - Phenomenology · Physics 2018-04-04 B. C. Allanach , Ben Gripaios , Tevong You

At the LHC, a TeV-scale leptoquark (LQ) that decays dominantly to a top quark ($t$) and a light charged lepton ($\ell=e,\mu$) would form a resonance system of \emph{boosted-$t$ $+$ high-$p_{\rm T}$-$\ell$}. We consider all possible vector…

High Energy Physics - Phenomenology · Physics 2020-07-06 Arvind Bhaskar , Tanumoy Mandal , Subhadip Mitra

Leptoquarks have been suggested to solve a variety of discrepancies between the expected and observed phenomenon. In this paper, we investigate the effect of scalar leptoquarks on the lepton flavor violating B meson rare decays which…

High Energy Physics - Phenomenology · Physics 2019-01-10 Jin-Huan Sheng , Ru-Min Wang , Ya-Dong Yang

Vector leptoquarks can address the lepton flavor universality anomalies in decays associated with the $b \to c \ell \nu$ and $b \to s \ell \ell$ transitions, as observed in recent years. Generically, these leptoquarks yield new sources of…

High Energy Physics - Phenomenology · Physics 2020-06-24 Wolfgang Altmannshofer , Stefania Gori , Hiren H. Patel , Stefano Profumo , Douglas Tuckler

We investigate the current LHC bounds on New Physics (NP) that contributes to $\bar B \to D^{(*)} l\bar\nu$ for $l = (e,\mu,\tau)$ by considering both leptoquark (LQ) models and an effective-field-theory (EFT) Hamiltonian. Experimental…

High Energy Physics - Phenomenology · Physics 2022-08-23 Syuhei Iguro , Michihisa Takeuchi , Ryoutaro Watanabe

The measurements of $R_K^{(*)}$ and $R_{D}^{(*)}$ by BaBar, Belle and the LHCb collaborations could be showing a hint of lepton flavor universality violation that can be accommodated by the presence of suitable leptoquarks at the TeV scale.…

High Energy Physics - Phenomenology · Physics 2018-12-20 Ezequiel Alvarez , Leandro Da Rold , Aurelio Juste , Manuel Szewc , Tamara Vazquez Schroeder

$SU(2)_L$-invariance links charged dilepton and dineutrino couplings. Phenomenological implications are worked out for flavor changing neutral currents involving strange, charm, beauty and top quark transitions in a model-independent way.…

High Energy Physics - Phenomenology · Physics 2022-02-23 Rigo Bause , Hector Gisbert , Marcel Golz , Gudrun Hiller

$U(1)^\prime$ extensions of the standard model with generation-dependent couplings to quarks and leptons are investigated as an explanation of anomalies in rare $B$-decays, with an emphasis on stability and predictivity up to the Planck…

High Energy Physics - Phenomenology · Physics 2022-02-02 Rigo Bause , Gudrun Hiller , Tim Höhne , Daniel F. Litim , Tom Steudtner

$B$-physics data and flavor symmetries suggest that leptoquarks can have masses as low as few ${\cal{O}}(\mbox{TeV})$, predominantly decay to third generation quarks, and highlight $pp \to b \mu \mu$ signatures from single production and…

High Energy Physics - Phenomenology · Physics 2018-04-11 Gudrun Hiller , Dennis Loose , Ivan Nisandzic

LHCb has reported hints of lepton-flavor universality violation in the rare decays $B \to K^{(*)} \ell^+\ell^-$, both in high- and low-$q^2$ bins. Although the high-$q^2$ hint may be explained by new short-ranged interactions, the low-$q^2$…

High Energy Physics - Phenomenology · Physics 2020-05-20 Wolfgang Altmannshofer , Michael J. Baker , Stefania Gori , Roni Harnik , Maxim Pospelov , Emmanuel Stamou , Andrea Thamm

We discuss a model that can accommodate the $B$-physics anomalies, based on combining two scalar leptoquarks, $R_2$ and $S_3$, of mass $\mathcal{O}(1\,\mathrm{TeV})$, and that we proposed in our previous paper. We update the analysis of its…

High Energy Physics - Phenomenology · Physics 2022-06-22 Damir Bečirević , Ilja Doršner , Svjetlana Fajfer , Darius A. Faroughy , Florentin Jaffredo , Nejc Košnik , Olcyr Sumensari

In recent times, one of the strongest hints of Physics Beyond the Standard Model (BSM) has been the anomaly in the ratios $R_D$ and $R_{D^\ast}$ measured in the charged current decays of $B$-mesons. In this work, we perform a comprehensive…

High Energy Physics - Phenomenology · Physics 2018-12-26 Aleksandr Azatov , Debjyoti Bardhan , Diptimoy Ghosh , Francesco Sgarlata , Elena Venturini

We investigate the ability of the $S_3$ scalar leptoquark to address the recent hints of lepton universality violation in $B$ meson decays. The $S_3$ leptoquark with quantum numbers $(\overline{\mathbf{3}},\mathbf{3},1/3)$ naturally emerges…

High Energy Physics - Phenomenology · Physics 2017-11-29 Ilja Doršner , Svjetlana Fajfer , Darius A. Faroughy , Nejc Košnik

While the LHC has not directly observed any new particle so far, experimental results from LHCb, BELLE and BABAR point towards the violation of lepton flavour universality in $b\to s\ell^{+}\ell^{-}$ and $b\to c\ell\nu$. In this context,…

High Energy Physics - Phenomenology · Physics 2018-06-13 Dario Müller

We attempt to explain recent anomalies in semileptonic $B$ decays at LHCb via a composite Higgs model, in which both the Higgs and an $SU(2)_L$-triplet leptoquark arise as pseudo-Goldstone bosons of the strong dynamics. Fermion masses are…

High Energy Physics - Phenomenology · Physics 2015-06-12 Ben Gripaios , Marco Nardecchia , S. A. Renner