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TH Articles

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2021-12-03
08:03
Estimating the thermal photon production rate using lattice QCD / Török, Csaba (U. Mainz, PRISMA) ; Cè, Marco (CERN) ; Harris, Tim (Edinburgh U.) ; Krasniqi, Ardit (U. Mainz, PRISMA) ; Meyer, Harvey B. (U. Mainz, PRISMA ; Helmholtz Inst., Mainz ; Darmstadt, GSI) ; Toniato, Arianna (U. Mainz, PRISMA)
We present results for the photon emission rate determined from the transverse channel vector correlator at fixed spatial momentum using two flavors of dynamical Wilson fermions at $T\sim$250 MeV. We estimate the transverse channel spectral function using the continuum extrapolated correlator by applying various fit ansätze with a smooth matching to the NLO perturbative result. [...]
arXiv:2112.00563; CERN-TH-2021-171.- 2021 - 9 p. - Published in : PoS: LATTICE2021 (2021) , pp. 172 Fulltext: PDF;
In : 38th International Symposium on Lattice Field Theory, Online, 26 - 30 Jul 2021, pp.172

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2021-11-29
04:01
Mounting Evidence for the Violation of Lepton Flavor Universality / Crivellin, Andreas (Zurich U. ; PSI, Villigen ; CERN) ; Hoferichter, Martin (Bern U.)
The Standard Model (SM) of particle physics was finalized in its current form in the mid-1970s, and has been extensively tested and confirmed ever since, with the discovery of the Higgs boson in 2012 being the last missing piece. While no new particles have been directly discovered at the Large Hadron Collider (LHC) at CERN so far, precision observables sensitive to quantum effects of new particles have accumulated intriguing hints for physics beyond the SM. [...]
arXiv:2111.12739; CERN-TH-2021-193; PSI-PR-21-26; ZU-TH 55/21.- 2021 - 3 p. - Published in : Science 374 (2021) 1051 Fulltext: PDF;

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2021-11-24
04:18
Likelihood analysis of the flavour anomalies and $g-2$ in the general two Higgs doublet model / Athron, Peter (Nanjing Normal U. ; Monash U.) ; Balazs, Csaba (Monash U.) ; Gonzalo, Tomás E. (RWTH Aachen U.) ; Jacob, Douglas (Monash U.) ; Mahmoudi, Farvah (IP2I, Lyon ; CERN) ; Sierra, Cristian (Monash U.)
We present a likelihood analysis of the general two Higgs doublet model, using the most important currently measured flavour observables, in view of the anomalies in charged current tree-level and neutral current one-loop rare decays of $B$ mesons in $b\to c l \overline{\nu}$ and $b\to s\mu^{+}\mu^{-}$ transitions, respectively. We corroborate that the model explains the latter and it is able to simultaneously fit the experimental values of the $R(D)$ ratio at $1\sigma$, but it can not accommodate the $R(D^{*})$ and $F_{L}(D^{*})$ observables. [...]
arXiv:2111.10464; CERN-TH-2021-194; TTK-21-47.- 2022-01-10 - 49 p. - Published in : JHEP 01 (2022) 037 Fulltext: 2111.10464 - PDF; JHEP 01 (2020) 037 - PDF; document - PDF;

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2021-11-17
06:21
Vacuum correlators at short distances from lattice QCD / Harris, Tim (Edinburgh U.) ; Cè, Marco (CERN) ; Meyer, Harvey B. (U. Mainz, PRISMA ; Mainz U., Inst. Kernphys. ; Darmstadt, GSI) ; Toniato, Arianna (U. Mainz, PRISMA) ; Török, Csaba (U. Mainz, PRISMA)
We propose a method to help control cutoff effects in the short-distance contribution to integrated correlation functions, such as the hadronic vacuum polarization (HVP), using the corresponding screening correlators computed at finite temperature. The strategy is investigated with Wilson fermions at leading order, which reveals a logarithmically-enhanced lattice artifact in the short-distance contribution, whose coefficient is determined at this order. [...]
arXiv:2111.07948; CERN-TH-2021-189.- 2021 - 9 p. - Published in : PoS: LATTICE2021 (2021) , pp. 572
Fulltext: PDF;
In : 38th International Symposium on Lattice Field Theory, Online, 26 - 30 Jul 2021, pp.572

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2021-11-05
07:18
Fiducial cross sections for the lepton-pair-plus-photon decay mode in Higgs production up to NNLO QCD / Chen, X. (KIT, Karlsruhe, TP ; KIT, Karlsruhe, IAP) ; Gehrmann, T. (Zurich U.) ; Glover, E.W. N. (Durham U., IPPP) ; Huss, A. (CERN)
The rare three-body decay of a Higgs boson to a lepton-antilepton pair and a photon is starting to become experimentally accessible at the LHC. We investigate how higher-order QCD corrections to the dominant gluon-fusion production process impact on the fiducial cross sections in this specific Higgs decay mode for electrons and muons. [...]
arXiv:2111.02157; ZU-TH 52/21; KA-TP-23-2021; IPPP/21/42; P3H-21-078; CERN-TH-2021-165.- 2022-01-12 - 16 p. - Published in : JHEP 2201 (2022) 053 Fulltext: 2111.02157 - PDF; document - PDF;

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2021-10-23
04:05
Operator growth in 2d CFT / Caputa, Pawel (Warsaw U.) ; Datta, Shouvik (CERN)
We investigate and characterize the dynamics of operator growth in irrational two-dimensional conformal field theories. By employing the oscillator realization of the Virasoro algebra and CFT states, we systematically implement the Lanczos algorithm and evaluate the Krylov complexity of simple operators (primaries and the stress tensor) under a unitary evolution protocol. [...]
arXiv:2110.10519; CERN-TH-2021-151.- 2021-12-27 - 48 p. - Published in : JHEP 2112 (2021) 188 Fulltext: document - PDF; 2110.10519 - PDF;

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2021-10-16
04:08
Flipped SU(5) GUT phenomenology: proton decay and $\mathbf {g_\mu - 2}$ / Ellis, John (King's Coll. London ; CERN ; NICPB, Tallinn) ; Evans, Jason L. (Tsung-Dao Lee Inst., Shanghai) ; Nagata, Natsumi (Tokyo U.) ; Nanopoulos, Dimitri V. (Texas A-M ; HARC, Woodlands ; Athens Academy) ; Olive, Keith A. (Minnesota U., Theor. Phys. Inst.)
We consider proton decay and $g_\mu - 2$ in flipped SU(5) GUT models. We first study scenarios in which the soft supersymmetry-breaking parameters are constrained to be universal at some high scale $M_{in}$ above the standard GUT scale where the QCD and electroweak SU(2) couplings unify. [...]
arXiv:2110.06833; KCL-PH-TH/2021-76; CERN-TH-2021-154; ACT-4-21; MI-HET-765, UMN-TH-4105/21; FTPI-MINN-21/22.- 2021-12-15 - 26 p. - Published in : Eur. Phys. J. C 81 (2021) 1109 Fulltext: document - PDF; 2110.06833 - PDF;

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2021-10-14
04:53
R-Parity Violation Axiogenesis / Co, Raymond T. (Minnesota U., Theor. Phys. Inst.) ; Harigaya, Keisuke (CERN ; Princeton, Inst. Advanced Study) ; Johnson, Zachary (Michigan U., LCTP) ; Pierce, Aaron (Michigan U., LCTP)
We show that the rotation of the QCD axion field, aided by $B-L$ violation from supersymmetric $R$-parity violating couplings, can yield the observed baryon abundance. Strong sphaleron processes transfer the angular momentum of the axion field into a quark chiral asymmetry, which $R$-parity violating couplings convert to the baryon asymmetry of the Universe. [...]
arXiv:2110.05487; UMN-TH-4104/21; FTPI-MINN-21-21; CERN-TH-2021-147; LCTP-21-25.- 2021-11-26 - 51 p. - Published in : JHEP 2111 (2021) 210 Fulltext: document - PDF; 2110.05487 - PDF;

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2021-10-06
11:30
Logarithmic accuracy of angular-ordered parton showers / Bewick, Gavin (Durham U., IPPP) ; Ferrario Ravasio, Silvia (Durham U., IPPP) ; Richardson, Peter (Durham U., IPPP ; CERN) ; Seymour, Michael H. (Manchester U.)
We study the logarithmic accuracy of angular-ordered parton showers by considering the singular limits of multiple emission matrix elements. This allows us to consider different choices for the evolution variable and propose a new choice which has both the correct logarithmic behaviour and improved performance away from the singular regions. [...]
arXiv:1904.11866; MAN/HEP/2019/003; CERN-TH-2019-047; MCnet-19-08; IPPP/19/30.- 2020-04-03 - 28 p. - Published in : JHEP 2004 (2020) 019 Article from SCOAP3: PDF; Fulltext: PDF;

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2021-09-19
15:48
On the chiral anomaly and the Yang–Mills gradient flow / Lüscher, Martin (CERN ; Bern U. ; U. Bern, AEC)
There are currently two singularity-free universal expressions for the topological susceptibility in QCD, one based on the Yang-Mills gradient flow and the other on density-chain correlation functions. While the latter link the susceptibility to the anomalous chiral Ward identities, the gradient flow permits the emergence of the topological sectors in lattice QCD to be understood. [...]
arXiv:2109.07965; CERN-TH-2021-132.- 2021-12-10 - 9 p. - Published in : Phys. Lett. B 823 (2021) 136725 Fulltext: PDF; Fulltext from publisher: PDF;

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