Quark Matter Research Papers - Academia.edu (original) (raw)

2025, Chinese Physics C

The masses of pion and sigma meson modes, along with their dissociation in the quark medium, provide detailed spectral structures of the chiral partners. Collectivity has been observed in pA and pp systems both at LHC and RHIC. In this research, we studied the restoration of chiral symmetry by investigating the finite size effect on the detailed structure of chiral partners in the framework of the Nambu-Jona-Lasinio model. Their diffusion and conduction have been studied using this dissociation mechanism. It is determined that the masses, widths, diffusion coefficients, and conductivities of chiral partners merge at different temperatures in the restoration phase of chiral symmetry. However, merging points are shifted to lower temperatures when finite size effect is introduced into the picture. The strengths of diffusions and conductions are also reduced once the finite size is introduced in the calculations.

2025, Few-Body Systems

The properties of net kaon fluctuations in nuclear matter has been studied within Polyakov loop extended Nambu-Jona-Lasinio model. The ratio of fourth order moment to second order moment (kurtosis) and the third order moment to the second order moment (skewness) of strangeness fluctuations have been calculated and compared with the recent experimental results.

2025, Physical Review C

We study the correlations between quark-antiquark pairs in different quantum number channels in a deconfined plasma by using an effective model of QCD. Using the three flavour PNJL model, the finite temperature spectral functions for different mesonic states are studied at zero and nonzero quark chemical potentials. It is found that in the η channel resonance structures survive above the chiral transition temperature Tχ, while the kaonic states seem to get washed off just above Tχ. The sensitivity of the structures to the anomaly term are carefully investigated.

2025, The Indian Journal of Agricultural Sciences

The present study was conducted during kharif 2013, kharif 2014 and kharif 2015 at Regional Agricultural Research Station, Lam, Guntur, Andhra Pradesh, India. The aim of the present investigation was to evaluate four American cotton genotypes and to determine which have the greatest relative values of favourable alleles for the improvement of number of bolls/plant, boll weight (g), 2.5% span length (mm), bundle strength (g/tex), seed cotton yield/plant (g) and lint yield/plant (g) in the elite single cross cotton hybrid (NA 1325 × L 604). Based on the estimates of μG’ values the genotype Surabhi was noted with positive high μG’ value and may be used as source of favourable alleles for improving elite hybrid with respect to quality traits like bundle strength (μG’=1.830*) and 2.5% span length (μG’=1.325*). This improvement may be possible by transferring favourable alleles from Surabhi to NA 1325 through back crossing as it had high genetic affinity with NA 1325. For number of bolls/...

2025, International Journal of Theoretical Physics

This brief report is an extension of studies of J/Ψ, Ψ(2S) production in pp collisions at the BNL with E= √ s=200 GeV to E=510 GeV at PHENIX.

2025

Theoretical models suggest that the Quantum Chromo-Dynamics (QCD) phase diagram has a critical point demarcating the order of transition between the two phases: the hadron gas, in which the quarks are confined and the Quark-Gluon Plasma (QGP). The central goal of the experiments with relativistic heavy-ion collisions is to create and study such form of matter called the QGP and understand the QCD phase diagram. The STAR (Solenoidal Tracker At RHIC) detector is pertinent for the RHIC (Relativistic Heavy Ion Collider) energy scan program where we plan to explore this exciting physics possibility using heavy-ion collisions at various center of mass energies. A first test run with Au+Au collisions at √ s N N = 9.2 GeV took place in early 2008. We present the recent STAR results from this run of the identified particles (pion, kaon and proton) transverse momentum spectra and ratios. Also we shall present and discuss the results of the azimuthal anisotropy parameters (v 1 , v 2 ) along with the pion interferometry measurements. These recent results from Au+Au collisions at √ s N N = 9.2 GeV are compared with other SPS and RHIC measurements.

2025

We propose a theoretical framework for a new state of matter-Electronless Nuclear Matter (ENM)-where bare atomic nuclei are stably confined and bonded through structured magnetic fields, without the involvement of electrons. We formulate five fundamental laws governing the organization, stability, and bonding of such nuclei in high-intensity magnetic traps. A modified Schrödinger equation is introduced to describe the quantum behavior of bare nuclei under magnetic confinement, and a new class of magnetic potential wells is proposed as the organizing principle of nuclear lattices. We predict the emergence of nuclear crystals, exotic magnetic phases, and resonance modes unique to this electronless regime. This paradigm opens the possibility of a magneto-nuclear periodic table, redefines the concept of chemical bonding, and suggests the existence of matter in forms previously considered impossible. The framework has potential implications in astrophysical environments such as magnetars, as well as in ultrahigh-field laboratory experiments. This work invites experimentalists and theorists to explore post-electronic architectures of matter governed purely by nuclear and magnetic interactions.

2025, Journal of Physics G: Nuclear and Particle Physics

Hadronic to quark matter phase transition may occur inside neutron stars (NS) having central densities of the order of 3-10 times normal nuclear matter saturation density (n 0 ). The transition is expected to be a two-step process; transition from hadronic to 2-flavour matter and two-flavour to β equilibrated charge neutral three-flavour matter. In this paper we concentrate on the first step process and solve the relativistic hydrodynamic equations for the conversion front in presence of high magnetic field. Lorentz force due to magnetic field is included in the energy momentum tensor by averaging over the polar angles. We find that for an initial dipole configuration of the magnetic field with a sufficiently high value at the surface, velocity of the front increases considerably.

2025, Nuclear Physics A

A two phase cascade, LUCIFER I1 [l], developed for the treatment of ultra high energy Ion-Ion collisions is applied to the production of strangeness at SPS energies 6 = 17-20. This simulation is able to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by separating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after an appropriate delay, by a normal multiscattering of the resulting excited baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first cascade takes place. The chief result is a reconciliation of the important Drell-Yan measurements with the apparent success of standard cascades to describe the nucleon stopping and meson production in heavy ion experiments at the CERN SPS.

2025, arXiv (Cornell University)

Multiplicity dependencies of midrapidity p t distributions of identified charged particles in inelastic proton-proton (p+p) collisions at center-of-mass energy (s) 1/2 =7 TeV at the Large Hadron Collider (LHC), measured by ALICE Collaboration, have been analyzed. The combined minimum χ 2 fits with thermodynamically consistent Tsallis function as well as Hagedorn function with the embedded transverse flow have described quite well the p t spectra of the charged pions and kaons, protons and antiprotons in the studied ten different classes of charged-particle multiplicity density. The extracted effective temperatures T of thermodynamically consistent Tsallis function have demonstrated consistent rise with increasing the multiplicity of charged particles in p+p collisions at (s) 1/2 =7 TeV in agreement with the similar result obtained recently in p+p collisions at (s) 1/2 =13 TeV at the LHC. The corresponding T versus <dN ch /d> dependence in inelastic p+p collisions at (s) 1/2 =7 TeV is reproduced quite well by the simple power function with the same value (≈ 1/3) of exponent parameter as that extracted in inelastic p+p collisions at (s) 1/2 =13 TeV. The same power dependence between the energy density and effective temperature of the system is observed in inelastic p+p collisions at (s) 1/2 =7 and 13 TeV. It is found that the transverse (radial) flow emerges at <dN ch /d>  6 and then increases, becoming significant at higher multiplicity events in p+p collisions at (s) 1/2 =7 TeV. It is estimated from analysis of T 0 and 〈 〉 versus <dN ch /d> dependencies that the probable deconfinement phase transition in p+p collisions at (s) 1/2 =7 TeV occurs at <dN ch /d>  6.1±0.3, which is noticeably smaller of the corresponding recent estimate (<dN ch /d>  7.1±0.2) in p+p collisions at (s) 1/2 =13 TeV. The corresponding critical energy densities for probable deconfinement phase transition in p+p collisions at (s) 1/2 =7 and 13 TeV at the LHC have been estimated to be 0.67±0.03 GeV/fm 3 and 0.76±0.02 GeV/fm 3 , respectively.

2025, arXiv (Cornell University)

We derive a gauge-invariant low-energy effective model of the SU(2) Yang-Mills theory. We find that the effective gluon propagator belongs to the Gribov-Stingl type, irrespective of the gauge choice. In the maximally Abelian gauge, especially, we demonstrate that the model exhibits both quark confinement and gluon confinement: the Wilson loop average has area law and the Schwinger function violates reflection positivity. Moreover, we give a formula for the string tension calculable from the gluon propagator of the gauge-invariant field strength and gives a good estimate for the string tension. We discuss if quark confinement and gluon confinement are of the same origin attributed to the gluon propagator in the deep infrared momentum region.

2025, Physical review

We present results from simulations of Two Color QCD with two Wilson quark flavors in the presence of a quark chemical potential µ at two different lattice spacings. The equation of state, conformal anomaly, superfluid order parameter and Polyakov line are all discussed. Our results suggest that the transition from hadronic to quark matter, and that from confined to deconfined matter occur at distinct values of µ, consistent with the existence of a quarkyonic phase in this model.

2025, arXiv (Cornell University)

The DESY-Swansea Collaboration performed numerical simulations investigating SU(2) lattice gauge theory at non-zero chemical potential with one staggered quark flavour in the adjoint representation. This lattice model has similar features to QCD itself and its study gives interesting insights into some open problems of high density quark matter. In particular the rôle of the "sign problem" can be clarified in connection with diquark condensation and the phase diagram.

2025, Physical Review D

2025, The European Physical Journal A

Results are presented from a numerical study of lattice QCD with gauge group SU(2) and two flavors of Wilson fermion at non-zero quark chemical potential µ ≫ T . Studies of the equation of state, the superfluid condensate, and the Polyakov line all suggest that in addition to the low density phase of Bose-condensed diquark baryons, there is a deconfined phase at higher quark density in which quarks form a degenerate system, whose Fermi surface is only mildly disrupted by Cooper pair condensation.

2025

2025, Proceedings of Science

The application of the Maximum Entropy Method (MEM) to the analysis of lattice QCD correlation function is discussed. We obtain information on the mass spectrum of excited states of a number of hadrons by extracting hadronic spectral functions (SPF) from correlation functions. Tests, results, and limitations of the MEM algorithm are presented. The data sets are on lattices 20 3 × 32 covering over 10 meson states and 20 baryon states, with each state as a function of 26 quark masses.

2025

We propose that prime numbers form fundamental eigenstates of a symbolic Hilbert space from which spacetime, gravity, and quantum phenomena emerge through entropy minimization processes. This framework extends beyond pure theory: analysis of 3,781 pulsar frequencies reveals significant clustering around prime values (symbolic entropy H = 1.688 bits), while gravitational wave signals from black hole mergers show 87.5% alignment with prime frequencies, producing entropy reductions of 2.65-4.58 bits. We develop a mathematical formalism where natural numbers exist as quantum-like superpositions of prime factors, and demonstrate how Einstein's field equations emerge as a coarse-grained limit of symbolic entropy dynamics. While highly speculative, this approach offers testable predictions and provides a novel perspective on the relationship between number theory, physics, and information.

2025

In a simplified model we study how close can the result of a fast non-equilibrium process, like hadronization of quark matter in an expanding fireball, come to hadronic composition in equilibrium. In a chemical approach of in-medium quark fusion (A + B → C) we find that this depends on the time-integrated rate per volume multiplied by the conserved number of constituents. Ideal hadron gas equilibrium constrained by conservation laws, the fugacity parametrization, as well as linear and non-linear coalescence approaches are recognized as different approximations to this chemistry. It is shown that color confinement requires a dependence of the hadronization cross section on quark density.

2025, Journal of Physics G: Nuclear and Particle Physics

We investigate how the QCD equation of state can be reconstructed by a continous mass distribution of non-interacting ideal components. We find that adjusting the mass scale as a function of the temperature leads to results which are conform to the quasiparticle model, but a temperature independent distribution also may fit lattice simulation results. We interpret this as a support for the quark coalescence approach to quark matter hadronization.

2025, Journal of Physics G: Nuclear and Particle Physics

Hyperon and antihyperon production is investigated using two microscopical models: 1 the fast hadronization of quark matter as given by the ALCOR model; 2 string formation and fragmentation as in the HIJING/B model. We calculate the particle numbers and momentum distributions for Pb+Pb collisions at CERN SPS energies in order to compare the two models with each other and with the available experimental data. We show that these two theoretical approaches give similar yields for the hyperons, but strongly dier for antihyperons.

2025

We prove that a temperature independent mass distribution is identically zero below a mass threshold (mass gap) value, if the pressure satisfies certain inequalities. This supports the finding of a minimal mass in quark matter equation of state by numerical estimates and by substitution of analytic formulas. We present a few inequalities for the mass distribution based on the Markov inequality.

2025, Universal Scaling Law

This paper presents a comprehensive formulation of the Universal Scaling Law enhanced with explicit solitonic field parameters and resonance corrections. We establish a unified theoretical framework that bridges empirical scaling relationships, fundamental symmetries, and nonlinear field dynamics through solitonic resonance phenomena. The model systematically incorporates sectoral contributions from charge, isospin, spin, and generation fields, along with their cross-couplings and synchronization effects. We demonstrate how the enhanced framework successfully predicts energy spectra across multiple physical domains while revealing deep connections between scale invariance and emergence of solitonic resonance peaks. Numerical results confirm the predictive power of this approach for systems ranging from nuclear structure to fundamental particle interactions.

2025

A precise measurement of the atomic mass dependence of dimuon production induced by 800 GeV protons incident on targets of Â²H, C, Ca, Fe, and W is reported. The relative Drell-Yan yield per nucleon, R = Y{sub A}/Y{sub 2{sub H}}, is sensitive to modifications of the antiquark sea in nuclei. No effect is seen for the range of target-quark momentum

2025

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, rccommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

2025, Cambridge Open Engage

The value of gravitational constant has been measured after the 18th century by various methods (such as using the torsion balance, very cold atoms and atom interferometry) in the macroscopic scale, namely in the distance more than one micro meter from the matter. But its amount at the vicinity of matter (for example at 𝑟 < 2 fermi) has not yet been measured. It was not acceptable for me to use the current value of gravitation constant (which its value was derived in macroscopic scale) in the microscopic and subatomic scale. This was the idea that led to writing this article. Here we show that we are able to consider a large value for the gravitational constant, 𝐺, at the vicinity of matter (𝑟 < 2 𝑓𝑚). Here we show that there are no experimental barriers for this hypothesis. Today, the strong bonds between nucleons in the nucleus of an atom is explained by the strong nuclear force (strong interaction). In this article, we show that the idea of the dependence of 𝐺 on the distance from matter can pave the way to explain the strong bonds between nucleons by the force of gravity. In this article, we present a new formula for nuclear force, which, as you will see, has significant advantages over the Yukawa equation. In this article, we criticize Yukawa's theory and show that his theory has three major problems.

2025

The LHC quarkonium production measurements reveal a startling observation: the J/ψ, ψ(2S), χ_c1,2 and Υ(nS) p_ T-differential cross sections are compatible with one universal momentum scaling pattern. Considering also the absence of strong polarizations of directly and indirectly produced S-wave mesons, we are led to the conclusion that there is currently no evidence of a dependence of the partonic production mechanisms on the quantum numbers and mass of the final state. The experimental observations supporting this universal production scenario are remarkably significant, as shown by a new analysis approach, unbiased by specific theoretical calculations of partonic cross sections, which are only considered a posteriori, in comparisons with the data-driven results.

2025, Physics Letters B

Using data collected by the HERA-B experiment, we have measured the fraction of J/ψ's produced via radiative χ c decays in interactions of 920 GeV protons with carbon and titanium targets. We obtained R χ c = 0.32 ± 0.06 stat ± 0.04 sys... more

2025, Invariant relativistic theory of classical and quantum ideal gases

The work presents an invariant relativistic theory of classical and quantum ideal gases subject to the relativistic distributions of Maxwell-Boltzmann, Fermi-Dirac and Bose-Einstein. Without applying the Gibbs canonical distribution method and the principle of maximum entropy, an alternative theory of ideal gases has been developed based on finding the macroscopic characteristics of classical and quantum ideal gases (particle number density, pressure and average energy) by statistical averaging over relativistic-invariant velocity distributions (for Maxwell-Boltzmann gas) and moments (for the Fermi-Dirac and Bose-Einstein gas). For the first time, expressions have been found for the average and root-mean-square particle velocities, which are valid for any ratio of thermal energy and rest energy of particles. For the first time, the limiting velocity of particle flows of quantum relativistic ideal gases has been determined. It has also been established that all real-life relativistic quantum ideal gases have adiabatic exponents that satisfy a certain fundamental inequality. I. Invariant relativistic theory of classical ideal gas Annotation. The purpose of this study is to develop an original theory of a relativistic ideal gas and to prove the validity of the postulate of the special theory of relativity for the characteristic (i.e., arithmetic mean, rootmean-square) velocities of particles of a relativistic ideal gas even in the massless limit. In this work, the following original methods are used for the first time in the theory of a relativistic ideal gas: the method of nonlinear transformation to prove of the distribution function to find the distribution function of the velocities of particles of a relativistic ideal gas; the equation of state of a relativistic ideal gas was first obtained by averaging the relativisticinvariant components of the energy-momentum tensor of a system of noninteracting particles, i.e. ideal gas by the distribution function of the velocities of their particles. The uniqueness and definiteness of the distribution function of the velocities of the particles of a relativistic ideal gas are proved on the basis of the well-known relativistic invariance of the distribution function. For the first time, expressions were obtained for the arithmetic mean and mean square velocities of particles of a relativistic ideal gas. For the first time, a fundamental conclusion is made about the validity of the postulates of the special theory of relativity for the characteristic velocities of particles of a relativistic ideal gas. An equation of state for a relativistic ideal gas is obtained, which relates its pressure, average energy density and temperature.

2025, Physical Review D, Volume 107, Issue 11, article id.114035

We calculate color screening mass in a thermalized and magnetized QCD matter in the frame of loop resummation theory without restriction to the magnetic field strength. Our full calculation covers the often used approximations for weak magnetic field at high temperature and strong magnetic field at low temperature. We find that while the magnetic field created in heavy ion collisions at RHIC and LHC energies is probably the strongest one in nature, its effect on the QCD matter is still weaker in comparison with the high temperature of the fireball, and therefore can safely be treated as a perturbation.

2025, Physical Review D, Volume 108, Issue 9, article id.L091503

We calculate the Debye screening mass in thermal, dense and magnetized QCD matter in the frame of resummed perturbation theory. In the limit of zero temperature, when the Landau energy level and Fermi surface of quarks match each other µ_q^2 = 2n|qB|, where q, µq and B are respectively the quark electric charge, chemical potential and external magnetic field, the screening mass diverges and the system is in the state of weakly interacting parton gas, which is very different from the known result of strongly interacting quark-gluon plasma at high temperature. The divergence disappears in thermal medium, but the screening mass oscillates with clear peaks at the matched magnetic field.

2025, arXiv (Cornell University)

We calculated the strong form factor and coupling constant for the J/ψD * D * vertex in a QCD sum rule calculation. We performed a double Borel sum rule for the three point correlation function of vertex considering both J/ψ and D *... more

2025, Silicon Polonide (SiPo) as Baryogenesis Catalyst in Neutron Star Crusts

We present conclusive evidence for silicon polonide (SiPo) as a CP-violating baryogenesis catalyst in neutron star crusts. Through controlled synthesis at the National Ignition Facility (ρ = 1.2 × 10 17 kg/m 3) and neutron irradiation tests at J-PARC, we demonstrate SiPo's stability under neutron star conditions. NICER observations of PSRs J1614-2230, J0931-1902, and J2129-0429 reveal characteristic 19.1 keV and 41.8 keV emission lines (SNR > 5), confirming SiPo's presence. The Dillip Cosmological Equation of State (DCEOS) framework predicts these results with < 5% deviation, establishing SiPo as the first experimentally validated material solution to Sakharov's conditions [1].

2025, Journal of Nuclear and Particle Physics

Transverse mass spectrum is one of the experimental parameter used to describe relativistic kinematic and mechanisms for hadron-hadron collisions and extended to nucleus-nucleus collisions. Charged pions emitted from Au+Au and Pb+Pb collisions at central rapidity (|𝑦𝑦| < 0.5) and impact parameter 𝑏𝑏 ≤ 3.4 𝑓𝑓𝑓𝑓 at different values of lab energies are investigated. The transverse mass distributions of secondaries depend on the energy of the interacting system. The experimental results compared with predictions by Quantum Molecular Dynamic model QMD and it ultra-relativistic implementation Ur-QMD using art version Ur-QMD-2.3. This model can give suitable distribution for transverse mass and describe experimental data for collision energy below 40 GeV. Above this energy, the hadron productions are not systematic which may due to the creation of different nuclear states of non-thermal equilibrium and high energy densities. The inverse slop parameter represents the effective temperature of the mechanism responsible for hadron productions. The temperature increases in regular tool with collision energy up to 40 GeV.

2025

2025, Physical Review Letters

The analysis of color-superconducting two-flavor deconfined quark matter at moderate densities is extended to include a particular spin-1 Cooper pairing of those quarks which do not participate in the standard spin-0 diquark condensate. (i) The relativistic spin-1 gap ∆ ′ implies spontaneous breakdown of rotation invariance manifested in the form of the quasi-fermion dispersion law. (ii) The critical temperature of the anisotropic component is approximately given by the relation T ′ c ≃ ∆ ′ (T = 0)/3. (iii) For massless fermions the gas of anisotropic Bogolyubov-Valatin quasiquarks becomes effectively gapless and two-dimensional. Consequently, its specific heat depends quadratically on temperature. (iv) All collective Nambu-Goldstone excitations of the anisotropic phase have a linear dispersion law and the whole system remains a superfluid. (v) The system exhibits an electromagnetic Meissner effect.

2025, arXiv (Cornell University)

Formalism for a unified description of distinct superfluid phases of a deconfined QCD matter at finite density together with the phase of spontaneously broken chiral symmetry is presented. Dispersion laws of the quasiquark excitations in... more

2025

Magnetized quark nuggets (MQNs) are theoretical objects composed of approximately equal numbers of up, down, and strange quarks and are candidate for dark matter consistent with the Standard Model. Tatsumi calculates they form a ferromagnetic fluid bound by strong nuclear forces and have a surface magnetic field B o between 10 11 and 10 12 T. We report 1) null results of MQNs with mass > 0.0001 kg in a 3 x 10 7 m 2 area of the Great Salt Lake in 0.25 y, excluding B o < 2 x 10 11 T, 2) positive results consistent with the passage of a MQN or Axion Quark Nugget (AQN) in a three-layer witness plate of an Irish peat bog, excluding B o < 4 x 10 11 T, and 3) too few events like Tunguska (1908) or Fukushima Earthquake (2011), excluding B o > 2 x 10 12 T. Radio frequency signals observed with the FORTE satellite in 1997 are compared to predicted emissions from MQNs after fly-by through earths atmosphere. MQNs might also be detected by magnetic fields of asteroids, collecting them for 4.6 Gy. Date submitted: 08 Jan 2020 Electronic form version 1.4 brought to you by CORE View metadata, citation and similar papers at core.ac.uk

2025

2025, arXiv: High Energy Physics - Phenomenology

The seed of the primordial magnetic field in the early universe has been attributed to various physical process in the early universe. In this work we provide a mechanism for the generation of a primordial magnetic field in the early universe via the collapse of Z(3)Z(3)Z(3) domains in the quark gluon plasma. The collapse of closed Z(3)Z(3)Z(3) domain walls that arise in the deconfined phase of the QCD (above Tsim200T\sim 200Tsim200 MeV) leads to the generation of vorticity and turbulence. The transmission coefficient of the uuu, ddd and sss are different across the Z(3)Z(3)Z(3) walls. This results in charge concentration at the wall boundary. The charge concentration on the boundary and the vorticity in the plasma generate a magnetic field. We estimate the magnitude of the magnetic field generated and find that it is of the order of 101710^{17}1017 G which is close to the equipartition value. The mechanism is independent of the order of the QCD phase transition.

2025

Baryon inhomogeneitites formed in the early universe are important as they affect the nucleosynthesis calculations. Since they are formed much before the nucleosynthesis epoch, neutrino inflation plays a crucial role in damping out these fluctuations. Now neutrinos, in turn, are affected by magnetic fields which may be present in the early universe. In this work we study the evolution of baryonic inhomogeneities due to neutrino induced dissipative processes in the presence of a background magnetic field. We find that at higher temperatures the dissipation of the inhomogeneities are enhanced as the magnetic field increases. Our study also shows that at lower temperatures the same magnetic field may produce less dissipation. Though we limit our study to temperatures below the quark-hadron transition we do establish that magnetic fields present in the early universe affect the dissipation of baryonic inhomogeneities.

2025, Arxiv preprint astro-ph/0205170

There is increasing observational evidence for the existence of strange stars: ultra-compact objects whose interior consists entirely of deconfined quark matter. If confirmed, their existence places constraints on the rate of formation of microscopic black holes in models which invoke a TeV-scale Planck mass. In such models, black holes can form with ∼ TeV masses through nuclear interactions of particles with PeV and greater energies. Once formed, these black hole states are unstable to Hawking radiation, and rapidly decay. However, if such a black hole forms in the interior of a strange star, the density is high enough that the decay may be counterbalanced by accretion, and the black hole can grow, leading to subsequent catastropic collapse of the star. A guaranteed source of ultra-high energy particles is provided by the cosmogenic Greisen neutrinos, as well as by ultra-high energy cosmic rays, and the implied lifetimes for strange stars are extremely short, contrary to observations. The observed lifetimes of strange star candidates thus effectively exclude Planck mass scales of less than ∼ 2 TeV with comparable black hole masses, for up to 2 extra dimensions. Seeding of strange star collapse in scenarios with a larger number of extra-dimensions or with higher mass black holes remains a possibility, and may provide another channel for the origin of gamma-ray bursts.

2025

The effect of strong magnetic fields on the properties of the pasta structures is calculated within a Thomas Fermi approach using relativistic mean field models to modulate stellar matter. It is shown how quantities such as the size of the clusters and Wigner-Seitz cells, the surface tension and the transition between configurations are affected. It is expected that these effects may give rise to large stresses in the pasta phase if the local magnetic field suffers fluctuations.

2025

Neutron stars allow us to explore matter under extreme densities, where phenomena like superfluidity significantly impact their thermal evolution. X-ray telescopes are capable of monitoring the cooling of neutron stars. Based on these observations, it seems that certain neutron stars experience rapid cooling, consistent with the apparition of the DURCA process, the most rapid cooling mechanism in neutron stars, while the others do not. This possible occurrence of fast cooling by the DURCA process depends on the stellar mass, the equation of state (EoS) of dense matter, and the superfluid properties of the stellar core. In view of the above, the present work focuses on neutron superfluidity and investigates how the 1S0 pairing gap, an essential aspect of superfluidity, suppresses the DURCA process and thereby impacts the cooling behavior of neutron stars. Using a metamodeling approach, we evaluated 10^4 EoSs, constrained by nuclear physics data and astrophysical observations via Bayesian inference. The proton fraction, pressure-density relationships, and their role in DURCA activation thresholds were analyzed. Introducing a rescaling factor sx we investigated the behavior of the 1S0 gap with baryon number density and its implications for DURCA suppression. Three DURCA scenarios-Always (fully active), Sometimes (partially active), and Never (fully suppressed)-were defined to study the interaction between the 1S0 gap and the EoS. Bayesian inference refined the posterior distributions of sx and baryon number densities so as to be consistent with nuclear and astrophysical constraints. The results indicate that the suppression of DURCA is highly sensitive to the density range in which the 1S0 gap appears; thus, it strongly links neutron star microphysics with observable cooling behavior. This work emphasizes the usefulness of metamodeling in connecting the microscopic properties of dense matter with the macroscopic phenomena of neutron stars.

2025

A few bubble chambers photographs for illustration of high-energy physics events at the high school level are here presented after briefly recalling some basic concepts of particle accelerators, bubble chambers and conserva tion laws in particle physics. Each photograph has a relevance for the understanding of particle physics concepts and of the methods used for analysis.

2025, arXiv (Cornell University)

We have recently introduced a realistic, covariant, interpretation for the reduction process in relativistic quantum mechanics. The basic problem for a covariant description is the dependence of the states on the frame within which collapse takes place. A suitable use of the causal structure of the devices involved in the measurement process allowed us to introduce a covariant notion for the collapse of quantum states. However, a fully consistent description in the relativistic domain requires the extension of the interpretation to quantum fields. This extension is far from straightforward. Besides the obvious difficulty of dealing with the infinite degrees of freedom of the field theory, one has to analyze and solve the objections raised by Sorkin concerning the impossibility of ideal measurements in quantum field theory. Here we show that in order to retain a causal theory it is necessary to modify the standard Wigner expression for the cases of partial causally connected local measurements. Our description could be experimentally tested. A verification of the new expression would give a stronger support to the realistic interpretations of the states in quantum mechanics.

2025, arXiv (Cornell University)

The possible role of a first order QCD phase transition at nonvanishing quark chemical potential and temperature for cold neutron stars and for supernovae is delineated. For cold neutron stars, we use the NJL model with nonvanishing color superconducting pairing gaps, which describes the phase transition to the 2SC and the CFL quark matter phases at high baryon densities. We demonstrate that these two phase transitions can both be present in the core of neutron stars and that they lead to the appearance of a third family of solution for compact stars. In particular, a core of CFL quark matter can be present in stable compact star configurations when slightly adjusting the vacuum pressure to the onset of the chiral phase transition from the hadronic model to the NJL model. We show that a strong first order phase transition can have strong impact on the dynamics of core collapse supernovae. If the QCD phase transition sets in shortly after the first bounce, a second outgoing shock wave can be generated which leads to an explosion. The presence of the QCD phase transition can be read off from the neutrino and antineutrino signal of the supernova.

2025, Springer eBooks

We present results for the spin-1 color-spin-locking (CSL) phase using a NJL-type model in two-flavor quark matter for compact stars applications. The CSL condensate is flavor symmetric and therefore charge and color neutrality can easily be satisfied. We find small energy gaps --~ 1 MeV, which make the CSL matter composition and the EoS not very different from the normal quark matter phase. We keep finite quark masses in our calculations and obtain no gapless modes that could have strong consequences in the late cooling of neutron stars. Finally, we show that the region of the phase diagram relevant for neutron star cores, when asymmetric flavor pairing is suppressed, could be covered by the CSL phase.

2025, arXiv (Cornell University)

Schwinger's boson solution for massless fermions in QED in 1+1D has been applied and generalized to quarks interacting in QED and QCD interactions, leading to stable and confined open-string QED and QCD boson excitations of the quark-QCD-QED system in 1+1D. Just as the open-string QCD excitations in 1+1D can be the idealization of QCD mesons with a flux tube in 3+1D, so the open-string QED excitations in 1+1D may likewise be the idealization of QED mesons with masses in the tens of MeV region, corresponding possibly to the anomalous X17 and E38 particles observed recently. A further search for bound states of quarks interacting in the QED interaction alone leads to the examination on the stability of the QED neutron, consisting of two d quarks and one u quark. Theoretically, the QED neutron has been found to be stable and estimated to have a mass of 44.5 MeV, whereas the analogous QED proton is unstable, leading to a long-lived QED neutron that may be a good candidate for the dark matter.