arXiv subjects

Sophie Renner

Publications and source records attributed to Sophie Renner.

22 records · Page 2Linked to original sources

arXiv2019

Matching for FCNC effects in the flavour-symmetric SMEFT

We calculate the complete tree and one-loop matching of the dimension 6 Standard Model Effective Field Theory (SMEFT) with unbroken $U(3)^5$ flavour symmetry to the operators of the Weak Effective Theory (WET) which are responsible for flavour changing neutral current effects among down-type quarks. We also explicitly calculate the effects of SMEFT corrections to input observables on the WET Wilson coefficients, a necessary step on the way to a well-defined, complete prediction. These results will enable high-precision flavour data to be incorporated into global fits of the SMEFT at high energies, where the flavour symmetry assumption is widespread.

hep-ph↗

arXiv2018

Maximal Flavour Violation: a Cabibbo mechanism for leptoquarks

We propose a mechanism that allows for sizeable flavour violation in quark-lepton currents, while suppressing flavour changing neutral currents in quark-quark and lepton-lepton sectors. The mechanism is applied to the recently proposed 4321 renormalizable model, which can accommodate the current experimental anomalies in $B$-meson decays, both in charged and neutral currents, while remaining consistent with all other indirect flavour and electroweak precision measurements and direct searches at high-$p_T$. To support this claim, we present an exhaustive phenomenological survey of this fully calculable UV complete model and highlight the rich complementarity between indirect and direct searches.

hep-ph↗

arXiv2018

A flavoured dark sector

We explore the phenomenology of a QCD-like dark sector which confines around the GeV scale. The dark sector inherits a flavour structure from a coupling between dark quarks and SM quarks via a heavy mediator, which leads to exciting new phenomena. While stable baryonic bound states are the dark matter candidates, the phenomenology is dominated by the lightest composite mesons, the dark pions, which can have decay lengths ranging from millimetres to hundreds of meters. For masses below 1.5 GeV, their exclusive decays to SM mesons are calculated for the first time by matching both dark and visible sectors to a chiral Lagrangian. Constraints from big bang nucleosynthesis, dark matter direct detection and flavour single out a small region of allowed parameter space for dark pion masses below 5 GeV. It is best probed by the fixed target experiments NA62 and SHiP, where dark pions can be produced copiously in rare decays like B to K piD. Heavier dark pions are best searched for at the LHC, where they decay after hadronisation to produce jets which emerge into SM states within the detector. Here the flavour structure ensures different flavours emerge on different length scales, leading to a striking new feature in the emerging jets signature.

hep-ph↗

arXiv2017

Exploring Peaks and Valleys in the Diphoton Spectrum

We investigate the effects of resonance-continuum interference on the diphoton spectrum in the presence of a new spin-0 or spin-2 state produced via gluons or quarks and decaying to pairs of photons. Interference effects can significantly influence the extraction of resonance masses and widths from the diphoton spectrum, particularly in the case of a spin-2 resonance produced via quarks. We illustrate these effects via a binned likelihood analysis of LHC diphoton data at both 8 and 13 TeV.

hep-ph↗