We investigate how a lepton asymmetry impacts the cosmic trajectory in the QCD phase diagram. We study the evolution of chemical potentials during the QCD epoch of the early Universe using susceptibilities from lattice QCD to interpolate between an ideal quark gas and an ideal hadron resonance gas. The lepton asymmetry affects the evolution of all chemical potentials. The standard cosmic trajectory is obtained assuming tiny lepton and baryon asymmetries. For larger lepton asymmetry, the charge chemical potential exceeds the baryon chemical potential before pion annihilation.
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http://dx.doi.org/10.1103/PhysRevLett.121.201302 | DOI Listing |
Phys Rev Lett
November 2024
Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University, 52056 Aachen, Germany and Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA.
The phenomena of dark matter and the baryon asymmetry pose two of the most pressing questions in today's fundamental physics. Conversion-driven freeze-out has emerged as a successful mechanism to generate the observed dark matter relic density. It supports thermalization of dark matter despite its very weak couplings, aligning with the null results from direct and indirect detection experiments.
View Article and Find Full Text PDFPhys Rev Lett
October 2024
Departamento de Física and IFIBA, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 1 (1428) Buenos Aires, Argentina.
We present a next-to-next-to-leading order (NNLO) global QCD analysis of the proton's helicity parton distribution functions, the first of its kind. To obtain the distributions, we use data for longitudinal spin asymmetries in inclusive and semi-inclusive lepton-nucleon scattering as well as in weak-boson and hadron or jet production in proton-proton scattering. We analyze the data using QCD perturbation theory at NNLO accuracy, employing approximations provided by the threshold resummation formalism in cases where full NNLO results for partonic hard-scattering functions are not readily available.
View Article and Find Full Text PDFPhys Rev Lett
March 2024
State Key Laboratory of Particle Detection and Electronics, Beijing 100049, Hefei 230026, People's Republic of China.
By analyzing 7.33 fb^{-1} of e^{+}e^{-} annihilation data collected at center-of-mass energies between 4.128 and 4.
View Article and Find Full Text PDFPhys Rev Lett
November 2023
We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189 fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector.
View Article and Find Full Text PDFEur Phys J C Part Fields
October 2023
Dipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, 20133 Milan, Italy.
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