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Related papers: Mass Mixing between QCD Axions

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Hidden axions may be coupled to the standard model particles through a kinetic or mass mixing with QCD axion. We study a scenario in which a hidden axion constitutes a part of or the whole of dark matter and decays into photons through the…

High Energy Physics - Phenomenology · Physics 2015-06-22 Tetsutaro Higaki , Naoya Kitajima , Fuminobu Takahashi

In this conference proceeding, I discuss in detail the deconfinement to quark matter that takes place at large densities and/or temperatures. The first-order phase transition that is assumed to appear beyond a critical point gives rise to…

Nuclear Theory · Physics 2018-01-26 Veronica Dexheimer

I review arguments for the existence of a critical point E in the QCD phase diagram as a function of temperature T and baryon chemical potential \mu. I describe how heavy ion collision experiments at the SPS and RHIC can discover the…

High Energy Physics - Phenomenology · Physics 2009-10-31 Krishna Rajagopal

We show that axion phenomenology may be significantly different than conventionally assumed in theories which exhibit late phase transitions (below the QCD scale). In such theories one can find multiple pseudoscalars with axion-like…

High Energy Physics - Phenomenology · Physics 2009-11-11 David B. Kaplan , Kathryn M. Zurek

In nucleus-nucleus collisions at ultra-relativistic energies matter is formed with initial energy density significantly exceeding the critical energy density for the transition from hadronic to partonic matter. We will review the…

Nuclear Experiment · Physics 2009-11-10 P. Braun-Munzinger

The transition temperature ($T_c$) of QCD is determined by Symanzik improved gauge and stout-link improved staggered fermionic lattice simulations. We use physical masses both for the light quarks ($m_{ud}$) and for the strange quark…

High Energy Physics - Lattice · Physics 2008-11-26 Y. Aoki , Z. Fodor , S. D. Katz , K. K. Szabo

I give a brief overview of our current understanding of the QCD phase diagram at finite temperature and baryon density. I emphasize phase transitions which occur at high density and low temperature (relative to the QCD scale), such as…

High Energy Physics - Phenomenology · Physics 2007-05-23 Stephen D. H. Hsu

QCD axions are at the crossroads of QCD topology and Dark Matter searches. We present here the current status of topological studies on the lattice, and their implication on axion physics. We outline the specific challenges posed by lattice…

High Energy Physics - Lattice · Physics 2020-08-26 Maria Paola Lombardo , Anton Trunin

In this work, we investigate the effective parameter space associated with the axion mass and the axion decay constant in both the light and heavy QCD axion scenarios. We initiate our discussion by considering the simplest case of two…

High Energy Physics - Phenomenology · Physics 2025-12-30 Hai-Jun Li

We revisit the joint constraints in the mixed hot dark matter scenario in which both thermally produced QCD axions and relic neutrinos are present. Upon recomputing the cosmological axion abundance via recent advances in the literature, we…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-13 Francesco D'Eramo , Eleonora Di Valentino , William Giarè , Fazlollah Hajkarim , Alessandro Melchiorri , Olga Mena , Fabrizio Renzi , Seokhoon Yun

We improve the estimate of the axion CDM energy density by considering the new values of current quark masses, the QCD phase transition effect and a possible anharmonic effect.

High Energy Physics - Phenomenology · Physics 2009-01-06 Kyu Jung Bae , Ji-Haeng Huh , Jihn E. Kim

We propose a novel and generalized mechanism, dubbed stochastic axion mixing. In a multi-axion framework, this mixing occurs naturally provided that the masses of all ultra-light axion-like particles (ALPs) are distinct and lighter than the…

High Energy Physics - Phenomenology · Physics 2026-05-01 Hai-Jun Li

Thermal axion production in the early universe goes through several mass thresholds, and the resulting rate may change dramatically across them. Focusing on the KSVZ and DFSZ frameworks for the invisible QCD axion, we perform a systematic…

High Energy Physics - Phenomenology · Physics 2021-11-04 Francesco D'Eramo , Fazlollah Hajkarim , Seokhoon Yun

The string axiverse presents a fascinating and complex landscape for axion physics. In this work, we study axion mass mixing within the type IIB string axiverse, focusing specifically on the LARGE volume scenario (LVS) axiverse. The LVS…

High Energy Physics - Theory · Physics 2025-04-15 Hai-Jun Li , Yu-Feng Zhou

We discuss the status of thermal model descriptions of particle ratios in central nucleus-nucleus collisions at ultra-relativistic energy. An alternative to the ``Cleymans-Redlich'' interpretation of the freeze-out trajectory is given in…

Nuclear Theory · Physics 2016-09-08 P. Braun-Munzinger , J. Stachel

On the basis of the NJL model as an effective theory of QCD and analogies with condensed matter physics, we extract simple physical pictures of the chiral phase transition at finite temperature $T$ and/or chemical potential $\mu$ and…

High Energy Physics - Phenomenology · Physics 2011-04-15 Teiji Kunihiro

We show how the properties of the QCD axion change in systems at finite baryonic density, such as neutron stars. At nuclear saturation densities, where corrections can be reliably computed, we find a mild reduction of the axion mass and up…

High Energy Physics - Phenomenology · Physics 2021-07-16 Reuven Balkin , Javi Serra , Konstantin Springmann , Andreas Weiler

The cosmological QCD transition affects primordial density perturbations. If the QCD transition is first order, the sound speed vanishes during the transition and density perturbations fall freely. For scales below the Hubble radius at the…

Astrophysics · Physics 2009-10-30 Christoph Schmid , Dominik J. Schwarz , Peter Widerin

QCD axions can be a substantial part of dark matter if their mass $m_a\sim10^{-5}$eV. Since the axions were created by the misalignment mechanism, their local energy spectrum density is large. Consequently, the axion-induced atomic…

High Energy Physics - Phenomenology · Physics 2023-06-21 Qiaoli Yang , Shiqin Dong

The present paper concludes our investigations on the QCD cross-over transition temperatures with 2+1 staggered flavours and one-link stout improvement. We extend our previous two studies [Phys. Lett. B643 (2006) 46, JHEP 0906:088 (2009)]…

High Energy Physics - Lattice · Physics 2014-11-21 Szabolcs Borsanyi , Zoltan Fodor , Christian Hoelbling , Sandor D Katz , Stefan Krieg , Claudia Ratti , Kalman K. Szabo