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Revisiting semileptonic $B$ meson decays at next-to-next-to-leading order / Egner, Manuel (KIT, Karlsruhe, TTP) ; Fael, Matteo (CERN) ; Schönwald, Kay (Zurich U.) ; Steinhauser, Matthias (KIT, Karlsruhe, TTP)
We compute next-to-next-to-leading order corrections to the semileptonic decay rate of $B$ mesons for arbitrary values of the final-state quark mass. For the contribution with one massive quark in the final state, we extend the literature result and obtain analytic expressions in terms of iterated integrals. [...]
arXiv:2308.01346; P3H-23-053; TTP23-030; ZU-TH 41/23; CERN-TH-2023-151.- 2023-09-18 - 23 p. - Published in : JHEP 2309 (2023) 112 Fulltext: 2308.01346 - PDF; document - PDF;

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$\tau _{B_{s}}/\tau _{B_{d}}$ and $\Delta \Gamma _{s}$ confront new physics in $b\rightarrow s\tau \tau $ / Bordone, Marzia (CERN) ; Fernández Navarro, Mario (Southampton U.)
Several new physics scenarios that address anomalies in $B$-physics predict an enhancement of $b \rightarrow s \tau \tau$ with respect to its Standard Model prediction. Such scenarios necessarily imply modifications of the lifetime ratio $\tau_{B_{s}}/\tau_{B_{d}}$ and the lifetime difference $\Delta\Gamma_{s}$. [...]
arXiv:2307.07013; CERN-TH-2023-138.- 2023-09-22 - 13 p. - Published in : Eur. Phys. J. C 83 (2023) 842 Fulltext: 2307.07013 - PDF; document - PDF;

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On the Ghost Problem of Conformal Gravity / Hell, Anamaria (Munich U., ASC) ; Lust, Dieter (Munich U., ASC ; Munich, Max Planck Inst.) ; Zoupanos, George (CERN ; Heidelberg U.)
We study the metric perturbations around the de Sitter and Minkowski backgrounds in Conformal Gravity. We confirm the presence of ghosts in both cases. [...]
arXiv:2306.13714; CERN-TH-2023-116; LMU-ASC 21/23; MPP-2023-134.- 2023-08-24 - 24 p. - Published in : JHEP 2308 (2023) 168 Fulltext: 2306.13714 - PDF; document - PDF;

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The Relation Between KMOC and Worldline Formalisms for Classical Gravity / Damgaard, Poul H. (Bohr Inst. ; CERN) ; Hansen, Elias Roos (Bohr Inst.) ; Planté, Ludovic (Bohr Inst.) ; Vanhove, Pierre (IPhT, Saclay)
We demonstrate the equivalence between KMOC and worldline formalisms for classical general relativity, highlighting how the Keldysh-Schwinger in-in formalism is contained in both of them even though the KMOC representation conventionally leads to the evaluation of scattering amplitudes with Feynman propagators. The relationship between the two approaches is illustrated in detail for the momentum kick at second Post-Minkowskian order..
arXiv:2306.11454; CERN-TH-2023-096; IPhT-t23/040; LAPTH-023/23.- 2023-09-11 - 34 p. - Published in : JHEP 2309 (2023) 059 Fulltext: 2306.11454 - PDF; document - PDF;

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Charged Higgs-Boson Decays into Quarks / Chang, Jamie (PSI, Villigen) ; Kirk, Fiona (Braunschweig, Phys. Tech. Bund. ; CERN) ; Mühlleitner, Margarete (KIT, Karlsruhe, TP) ; Spira, Michael (PSI, Villigen)
We consider the full genuine next-to-leading order SUSY-QCD corrections to the charged Higgs decays into quarks supplemented by the NNLO corrections to the effective top and bottom Yukawa couplings. The NNLO corrections to the effective top Yukawa coupling are a new ingredient of our analysis. [...]
arXiv:2306.11392; KA-TP-12-2023; PSI-PR-23-18; CERN-TH-2023-112.- 2023-08-19 - 22 p. - Published in : Nucl. Phys. B 995 (2023) 116330 Fulltext: Publication - PDF; 2306.11392 - PDF;

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Composing arbitrarily many $SU(N)$ fundamentals / Polychronakos, Alexios P. (City Coll., N.Y. ; CUNY, Graduate School - U. Ctr.) ; Sfetsos, Konstantinos (Athens U. ; CERN)
We compute the multiplicity of the irreducible representations in the decomposition of the tensor product of an arbitrary number $n$ of fundamental representations of $SU(N)$, and we identify a duality in the representation content of this decomposition. Our method utilizes the mapping of the representations of $SU(N)$ to the states of free fermions on the circle, and can be viewed as a random walk on a multidimensional lattice. [...]
arXiv:2305.19345; CERN-TH-2023-085.- 2023-08-08 - 25 p. - Published in : Nucl. Phys. B 994 (2023) 116314 Fulltext: 2305.19345 - PDF; Publication - PDF;

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Dark Sectors with Mass Thresholds Face Cosmological Datasets / Allali, Itamar J. (Tufts U.) ; Rompineve, Fabrizio (CERN ; Barcelona, IFAE ; Barcelona, Autonoma U.) ; Hertzberg, Mark P. (Tufts U.)
Interacting dark sectors may undergo changes in the number of their relativistic species during the early universe, due to a mass threshold $m$ (similar to changes in the Standard Model bath), and in doing so affect the cosmic history. When such changes occur close to recombination, i.e., for $m\sim (0.1-10)~\text{eV}$, the stringent bound on the effective number of neutrino species, $N_{\text{eff}}$, can be relaxed and the value of the Hubble expansion rate $H_0$ inferred from Cosmic Microwave Background (CMB) observations raised. [...]
arXiv:2305.14166; CERN-TH-2023-084.- 2023-07-15 - 36 p. - Published in : Phys. Rev. D 108 (2023) 023527 Fulltext: PDF;

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Precision CMB constraints on eV-scale bosons coupled to neutrinos / Sandner, Stefan (Valencia U., IFIC) ; Escudero, Miguel (CERN) ; Witte, Samuel J. (Amsterdam U. ; U. Amsterdam, GRAPPA ; ICC, Barcelona U.)
The cosmic microwave background (CMB) has proven to be an invaluable tool for studying the properties and interactions of neutrinos, providing insight not only into the sum of neutrino masses but also the free streaming nature of neutrinos prior to recombination. The CMB is a particularly powerful probe of new eV-scale bosons interacting with neutrinos, as these particles can thermalize with neutrinos via the inverse decay process, $\nu\bar{\nu} \rightarrow X$, and suppress neutrino free streaming near recombination -- even for couplings as small as $\lambda_\nu \sim \mathcal{O}(10^{-13})$. [...]
arXiv:2305.01692; IFIC/23-13; FTUV-23-0413.0599; CERN-TH-2023-073.- 2023-08-09 - 19 p. - Published in : Eur. Phys. J. C 83 (2023) 709 Fulltext: 2305.01692 - PDF; document - PDF;

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Non-singular pre-big bang scenarios from all-order $\alpha'$ correctionsNon-singular pre-big bang scenarios from all-order α′ corrections / Gasperini, M. (Bari U. ; INFN, Bari) ; Veneziano, G. (CERN ; College de France)
We reformulate in Hamiltonian language the recent proposal by Hohm and Zwiebach of an action yielding the most general $O(d,d)$-symmetric string cosmology equations, at tree-level in the string-loop expansion, but to all orders in the $\alpha'$ expansion. This allows us to give a simple characterization of a large class of non-singular, non-perturbative, pre-big bang scenarios smoothly interpolating between a low-energy initial accelerated (string frame) expansion and a phase of final (string and Einstein frame) decelerated expansion. [...]
arXiv:2305.00222; BA-TH/807-23; CERN-TH-2023-066.- 2023-07-18 - 20 p. - Published in : JHEP 2307 (2023) 144 Fulltext: document - PDF; 2305.00222 - PDF;

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The Hawking Energy in a Perturbed Friedmann-Lemaître Universe / Stock, Dennis (Geneva U., CAP ; Geneva U., Dept. Theor. Phys.) ; Di Dio, Enea (CERN) ; Durrer, Ruth (CERN)
Hawking's quasi-local energy definition quantifies the energy enclosed by a spacelike 2-sphere in terms of the amount of lightbending on the sphere caused by the energy distribution inside the sphere. This paper establishes for the first time a direct connection between the formal mathematical definition of a quasi-local energy and observations, in the context of cosmological perturbation theory. [...]
arXiv:2305.00711; CERN-TH-2023-063.- 2023-08-14 - 28 p.
Fulltext: 2305.00711 - PDF; document - PDF;

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