H2020Индивидуална стипендия2020–2022

TOFU · Testing leptOn Flavour Universality in excited strange mesons

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2020-05-01 → 2022-04-30
Финансиране от ЕС: 175 572 €
Участници: 1
Схема: MSCA-IF

Линиите свързват координатора с партньорите.

Накратко на български

Разпадите на странни B-мезони върху муони и тау-лептони се сравняват, за да се провери дали тези частици взаимодействат еднакво със силите в природата. Резултатите могат да подскажат за съществуването на нова сила, която не е описана в сегашния стандартен модел на физиката.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Testing leptOn Flavour Universality in excited strange mesons

This project revolves around testing one of the key assumptions of the Standard Model which describes all known particles and their interactions: lepton flavour universality. This assumption states that leptons (electrons and their heavier siblings, muons and taus) all have the exact same couplings to the forces of nature. However, recent measurements of three different experiments have shown hints that this assumption may not hold, which has major implications to the field of particle physics: it could even lead to the discovery of a new force of nature. For this project, I have been working on a measurement to study decays of strange B mesons (Bs) into excited strange D mesons (Ds*). In particular, I have compared of such decays with muons to those with taus in a ratio called R(Ds*). Compared to the previously performed analyses, this one has the advantage of having fewer backgrounds from excited states, which form a major uncertainty on the existing measurements. Another part of the project concerns the development of a validation framework to test the reconstruction software of the upgraded LHCb detector. In the upgraded detector, which is currently being commissioned, the hardware trigger is removed and replaced by a software trigger. In addition, the alignment and calibration of the detector is done in real-time, such that more stringent requirements can be placed on the data selection. Hence, the software must be very well tested before commissioning; otherwise valuable data will be lost.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

Our understanding of all known particles and their interactions is successfully described in the Standard Model (SM). It is, however, known to be incomplete since it does not explain e.g. dark matter, or the matter-antimatter asymmetry in the universe. Recently, several experiments found hints of physics beyond the SM, which must be further investigated.A key assumption of the SM is that leptons (electrons and their heavier siblings, muons and taus) have the exact same couplings to forces, called lepton universality. When testing this assumption using decays of so-called B mesons, three independent experiments found increased values for their decay rate to a D meson and tau lepton, compared to a D meson and a muon. This could be explained by the existence of new particles, such as leptoquarks, which couple more strongly to leptons with a higher mass.This proposal concerns a similar measurement using strange B mesons (Bs), which decay into strange D mesons (Ds). The D mesons that were measured before are extremely difficult to distinguish from their so-called resonance states, which are excitations of the D meson. Misidentifying these could wrongly increase the rate of tau decays of all three experiments. Ds mesons, on the other hand, have a different structure of resonances, and fewer exist that can mimic the signal. Additionally, these can be constrained using their well-defined kinematics. As such, an observation of non-universality in the Bs meson decays would provide conclusive evidence for the existence of physics beyond the SM.In 2021, the LHCb experiment will recommence data-taking with a completely new detector and reconstruction software. Dr. Klaver plays a key role in studying the impact of misaligned or misplaced detectors and detector defects of the upgrade detector. This proposal describes how a validation framework is to be set up to aid the commissioning of the new experiment. This secures future tests of lepton universality with high precision.

Оригинален текст от CORDIS (на английски).

Участници

STICHTING NEDERLANDSE WETENSCHAPPELIJK ONDERZOEK INSTITUTEN · UtrechtКоординаторНидерландия