Indirect and monojet constraints on scalar leptoquarks

This paper presents the prospects for a precise measurement of the branching fraction of the leptonic $$ {B}_c^{+} $$ B c + → τ+ντ decay at the Future Circular Collider (FCC-ee) running at the Z -pole. A detailed description of the simulation and analysis framework is provided. To select signal candidates, two Boosted Decision Tree algorithms are employed and optimised. The first stage suppresses inclusive $$ b\overline{b} $$ b b ¯ , $$ c\overline{c} $$ c c ¯ , and $$ q\overline{q} $$ q q ¯ backgrounds using event-based topological information. A second stage utilises the properties of the hadronic τ+→ π+π+π−$$ \overline{\nu} $$ ν ¯ τ decay to further suppress these backgrounds, and is also found to achieve high rejection for the B+→ τ+ντ background. The number of $$ {B}_c^{+} $$ B c + → τ+ντ candidates is estimated for various Tera-Z scenarios, and the potential precision of signal yield and branching fraction measurements evaluated. The phenomenological impact of such measurements on various New Physics scenarios is also explored.

Section: Leptoquarksmentioning

confidence: 76%

Prospects for $$ {B}_c^{+} $$→ τ +ντ at FCC-ee

Amhis

Hartmann

Helsens

et al. 2021

“…Recent theory work on scalar leptoquark searches can be found in [46][47][48][49][50][51][52][53][54][55], with [55] specifically focusing on leptoquarks that decay to top quarks and light charged leptons. The work of [48] uses a recast of the CMS multi-lepton search [56] to set a limit of 800 GeV on this scenario.…”

Section: Jhep08(2020)036mentioning

confidence: 99%

Constraining new physics with single top production at LHC

Stolarski

Tonero

2020

We study effects of beyond the Standard Model physics coupling third generation quarks to leptons of the first two generations. We parametrize these effects by dimension-six effective operators, and we also consider related simplified UV completions: scalar leptoquark and W models. We derive new constraints on these scenarios by using recent ATLAS measurements of differential cross sections of single top production in association with a W boson, and also show how these limits will evolve with future data. We also describe how the limits can be significantly improved by using ratios of differential distributions with different flavours of leptons.

“…Certain representations of leptoquarks under the SM gauge group are impossible to obtain in some string theory constructions, so any signal of such a LQ would immediately rule out a number of models [58]. Aside from any UV motivations for their existence, LQs near the weak scale have been well studied in the literature [59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74], and have been frequently appealed to in order to explain various low energy anomalies e.g. in B meson decays [75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92].…”

Section: Introductionmentioning

confidence: 99%

Searching for leptoquarks at future muon colliders

Asadi

Capdevilla

Cesarotti

et al. 2021

A high energy muon collider can provide new and complementary discovery potential to the LHC or future hadron colliders. Leptoquarks are a motivated class of exotic new physics models, with distinct production channels at hadron and lepton machines. We study a vector leptoquark model at a muon collider with $$ \sqrt{s} $$ s = 3, 14 TeV within a set of both UV and phenomenologically motivated flavor scenarios. We compute which production mechanism has the greatest reach for various values of the leptoquark mass and the coupling between leptoquark and Standard Model fermions. We find that we can probe leptoquark masses up to an order of magnitude beyond $$ \sqrt{s} $$ s with perturbative couplings. Additionally, we can also probe regions of parameter space unavailable to flavor experiments. In particular, all of the parameter space of interest to explain recent low-energy anomalies in B meson decays would be covered even by a $$ \sqrt{s} $$ s = 3 TeV collider.