Buonocore, Luca
(2020)
Ultimate precision for the Drell-Yan process: mixed QCDxQED(EW) corrections, final state radiation and power suppressed contributions.
[Tesi di dottorato]
| Tipologia del documento: |
Tesi di dottorato
|
| Lingua: |
English |
| Titolo: |
Ultimate precision for the Drell-Yan process: mixed QCDxQED(EW) corrections, final state radiation and power suppressed contributions |
| Autori: |
| Autore | Email |
|---|
| Buonocore, Luca | lbuono@na.infn.it |
|
| Data: |
13 Febbraio 2020 |
| Numero di pagine: |
168 |
| Istituzione: |
Università degli Studi di Napoli Federico II |
| Dipartimento: |
Fisica |
| Dottorato: |
Fisica |
| Ciclo di dottorato: |
32 |
| Coordinatore del Corso di dottorato: |
| nome | email |
|---|
| Capozziello, Salvatore | salvatore.capozziello@unina.it |
|
| Tutor: |
| nome | email |
|---|
| Francesco, Tramontano | [non definito] | | Massimiliano, Grazzini | [non definito] |
|
| Data: |
13 Febbraio 2020 |
| Numero di pagine: |
168 |
| Parole chiave: |
Drell-Yan, mixed QCD-EW radiative corrections, power corrections |
| Settori scientifico-disciplinari del MIUR: |
Area 02 - Scienze fisiche > FIS/02 - Fisica teorica, modelli e metodi matematici |
[error in script]
[error in script]
| Depositato il: |
31 Mar 2020 16:12 |
| Ultima modifica: |
08 Nov 2021 12:10 |
| URI: |
http://www.fedoa.unina.it/id/eprint/13156 |
Abstract
The discovery of the Higgs Boson at the Large Hadron Collider in 2012 represented
a breakthrough in particle physics, providing a strong confirmation of the mechanism
of Electro-Weak-Symmetry-Breaking, which is in turn responsible for the generation of elementary-particle masses.
The Higgs discovery, however, was not followed by any evidence
of physics Beyond the Standard Model, and it is difficult to reconcile
our current description of the fundamental particles and their interactions with long-standing problems
like neutrino masses, matter-anti matter asymmetry, the existence of dark matter and dark energy and the hierarchy problem.
The lack of new-physics signals has stimulated a new precision collider programme, which was made possible
by the advances on both the experimental and theoretical sides. Indeed, the precision target accuracy
expected by the end of the planned LHC data taking in 2038 is at the (sub)percent level.
For a meaningful comparison with experimental data, we need theoretical predictions which have a similar
level of accuracy. This translates into the necessity of computing higher order terms in perturbation theory,
known as radiative corrections in the language of Quantum Field Theory. At an hadronic collider
as the LHC the effects due to the strong interaction (described by Quantum CromoDynamics (QCD)) dominate.
In the last decades a big effort has been profused to compute QCD radiative corrections and nowadays
Next-to-Next-to Leading Order (NNLO) computations represent the state of the art for many $2\to2$ processes.
The production of a dilepton pair via the Drell-Yan mechanism has a
special place in the precision phenomenology program at LHC for its importance
in experimental calibrations and for the precise determination of important electro-weak (EW)
parameters such as the W mass. From the theoretical side, Drell-Yan is one of the most studied processes.
QCD corrections are known up to NNLO and in part at N$^3$LO, while EW corrections are known at NLO.
At this level of accuracy, it becomes relevant to assess the relative importance of the mixed QCD-EW corrections.
In this thesis, we set up a subtraction framework to compute the full set of
mixed QCD-EW(QED) corrections to the the Drell-Yan process at the differential level.
We rely on the transverse momentum resummation formalism to handle the
genuine NNLO-type infrared divergences associated to both initial and final state
radiation in the small transverse momentum limit, exploiting the corresponding results for heavy-quark pair production.
In particular, we have to deal with massive leptons in the final state
as the their mass acts as a regulator for final-state collinear divergences.
This may challenge the numerical stability since the physical lepton masses
are very small. We extensively study the radiation pattern of massive emitters,
building a dedicated momentum mapping which smoothly approaches the massless limit.
Furthermore, we study, for the first time, the leading power suppressed contributions appearing
at small transverse momenta, and we show that they are driven by final-state soft radiation.
As a validation of our construction, we show results both for the
inclusive and the relevant differential distribution
for the mixed QCD-QED corrections to the production of an on-shell Z boson.
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