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The Standard Model is in good shape, apart possibly from g_\mu - 2 and some niggling doubts about the electroweak data. Something like a Higgs boson is required to provide particle masses, but theorists are actively considering…

High Energy Physics - Phenomenology · Physics 2023-03-30 John Ellis

The hypothesis is proposed that under the approximation that the quantum equations of motion reduce to the classical ones, the quantum vacuum also reduces to the classical vacuum--the empty space. The vacuum energy of QED is studied under…

High Energy Physics - Theory · Physics 2007-05-23 Shi Qi

I present a concise review of the Higgs problem which plays a central role in particle physics today. The Higgs of the minimal Standard Model is so far just a conjecture that needs to be verified or discarded at the LHC. Probably the…

High Energy Physics - Phenomenology · Physics 2015-05-18 Guido Altarelli

We describe a wide class of inhomogeneous relativistic solutions that are well approximated on cosmological scales by solutions of Newtonian gravity. Error estimates measuring the difference between the Newtonian and relativistic solutions…

General Relativity and Quantum Cosmology · Physics 2014-06-06 Todd A. Oliynyk

We suggest a new perspective on the Cosmological Constant Problem by scrutinizing its standard formulation. In classical and quantum mechanics without gravity, there is no definition of the zero point of energy. Furthermore, the Casimir…

High Energy Physics - Theory · Physics 2014-09-25 Denis Bernard , André LeClair

Two problems are discussed here. The first one is the 0.4 dex discrepancy between the 7Li abundance derived from the spectra of metal-poor halo stars on the one hand, and from Big Bang nucleosynthesis, based on the cosmological parameters…

Many attempts to solve the Hubble tension with extended cosmological models combine an enhanced relic radiation density, acting at the level of background cosmology, with new physical ingredients affecting the evolution of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-16 Nils Schöneberg , Julien Lesgourgues , Deanna C. Hooper

The primordial lithium abundance inferred from observations of metal-poor stars is ~3 times smaller than the theoretical value in standard big bang nucleosynthesis (BBN) model. We assume a simple model including a sterile neutrino nu_H with…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-29 Hiroyuki Ishida , Motohiko Kusakabe , Hiroshi Okada

A cosmological model with a time-varying mass of electrons seems a promising solution for the so-called Hubble tension. We examine the big bang nucleosynthesis (BBN) constraints on the time-varying electron mass model, because a larger…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-01 Osamu Seto , Yo Toda

Cosmological and astrophysical measurements indicate that the universe contains a large amount of dark matter. A number of weak scale dark matter candidates have been proposed in extensions of the standard model. The potential to discover…

High Energy Physics - Phenomenology · Physics 2009-12-17 G. Bélanger

Severe methodological and numerical problems of the traditional quantum mechanical approach to the description of molecular systems are outlined. To overcome these, a simple alternative to the Born-Oppenheimer approximation is presented on…

Chemical Physics · Physics 2014-02-06 Irmgard Frank

Recently it has been argued that a correct reading of the quantum fluctuations of the vacuum could lead to a solution to the cosmological constant problem. In this work we critically examine such a proposal, finding it questionable due to…

General Relativity and Quantum Cosmology · Physics 2020-01-15 Gabriel R. Bengochea , Gabriel León , Elias Okon , Daniel Sudarsky

Observations of light isotopes in cosmic rays provide information on their origin and propagation in the Galaxy. Using the data collected by AMS-01 in the STS- 91 space mission, we compare the measurements on 1H, 2H, 3He and 4He with…

High Energy Astrophysical Phenomena · Physics 2017-08-23 N. Tomassetti

A new class of solutions to the electroweak hierarchy problem is presented that does not require either weak scale dynamics or anthropics. Dynamical evolution during the early universe drives the Higgs mass to a value much smaller than the…

High Energy Physics - Phenomenology · Physics 2015-12-02 Peter W. Graham , David E. Kaplan , Surjeet Rajendran

I try to revive, and possibly reconcile, a debate started a few years ago, about the relative roles of a bare cosmological constant and of a vacuum energy, by taking the attitude to try to get the most from the physics now available as…

General Relativity and Quantum Cosmology · Physics 2019-09-19 Massimo Cerdonio

The status of solutions to the ultra-high energy cosmic ray puzzle that involve particle physics beyond the standard model is reviewed. Signatures and experimental constraints are discussed for most proposals like the Z burst model and…

High Energy Physics - Phenomenology · Physics 2009-11-10 M. Kachelriess

The possible sources of light nuclei populations observed recently below the geomagnetic cutoff by the AMS experiment are discussed in terms of nuclear processes: fragmentation of the incoming flux of cosmic helium on atmospheric nuclei,…

Astrophysics · Physics 2009-11-06 L. Derome , M. Buenerd

Astrophysics and cosmology can be used to test the standard model of particle physics under conditions and over distance and time scales not accessible to laboratory experiments. Most of the astrophysical observations are in good agreement…

High Energy Physics - Phenomenology · Physics 2016-09-01 Arnon Dar

We consider the effects of uncertainties in nuclear reaction rates on the cosmological constraints on the decays of unstable particles during or after Big-Bang nucleosynthesis (BBN). We identify the nuclear reactions due to non-thermal…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-08 Richard H. Cyburt , John Ellis , Brian D. Fields , Feng Luo , Keith A. Olive , Vassilis C. Spanos

Of the light nuclides observed in the universe today, D, 3He, 4He, and 7Li are relics from its early evolution. The primordial abundances of these relics, produced via Big Bang Nucleosynthesis (BBN) during the first half hour of the…

Astrophysics · Physics 2007-05-23 Gary Steigman