Preprint

PUBDB-2023-00700

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Opportunistic CP Violation

Bonnefoy, Q.DESY* ; Gendy, E.Extern* ; Grojean, C. (Corresponding author)DESY* ; Ruderman, J. T.

2023

This record in other databases:  

Please use a persistent id in citations: doi:10.3204/PUBDB-2023-00700

Report No.: DESY-23-018; HU-EP-22/39; TUM-HEP-1453/23; arXiv:2302.07288

Abstract: In the electroweak sector of the Standard Model, CP violation arises through a very particular interplay between the three quark generations, as described by the Cabibbo--Kobayashi--Maskawa (CKM) mechanism and the single Jarlskog invariant $J_4$. Once generalized to the Standard Model Effective Field Theory (SMEFT), this peculiar pattern gets modified by higher-dimensional operators, whose associated Wilson coefficients are usually split into CP-even and odd parts. However, CP violation at dimension four, i.e., at the lowest order in the EFT expansion, blurs this distinction: any Wilson coefficient can interfere with $J_4$ and mediate CP violation. In this paper, we study such interferences at first order in the SMEFT expansion, $O(1/\Lambda^2)$, and we capture their associated parameter space via a set of 1551 linear CP-odd flavor invariants. This construction describes both new, genuinely CP-violating quantities as well as the interference between $J_4$ and CP-conserving ones. We call this latter possibility opportunistic CP violation. Relying on an appropriate extension of the matrix rank to Taylor expansions, which we dub Taylor rank, we define a procedure to organize the invariants in terms of their magnitude, so as to retain only the relevant ones at a given precision. We explore how this characterization changes when different assumptions are made on the flavor structure of the SMEFT coefficients. Interestingly, some of the CP-odd invariants turn out to be less suppressed than $J_4$, even when they capture opportunistic CPV, demonstrating that CP-violation in the SM, at dimension 4, is accidentally small.

Keyword(s): CP, violation ; dimension, 4 ; operator, higher-dimensional ; capture ; interference ; flavor ; effective field theory ; mediation ; structure ; electroweak interaction ; quark ; Jarlskog ; suppression ; Taylor expansion

Note: Now published on the arXiv: https://arxiv.org/abs/2302.07288

---

Contributing Institute(s):

1. Theorie-Gruppe (T)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)
2. DFG project 390833306 - EXC 2121: Quantum Universe (390833306) (390833306)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2023

---

Database coverage:
; Published

---

---

Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Journal Article Bonnefoy, Q. (Corresponding author)DESY* ; Gendy, E. ; Grojean, C.DESY* ; Ruderman, J. T.
Opportunistic CP violation
Journal of high energy physics 06(6), 141 (2023) [10.1007/JHEP06(2023)141]2023     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

---