scholarly journals Open charm and charmonium states in strong magnetic fields

2021 ◽  
pp. 2150064
Author(s):  
Amruta Mishra ◽  
S. P. Misra
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Constituent Quark ◽  
Open Charm ◽  
Charm Mesons ◽  
Strong Magnetic Fields ◽  
Decay Widths ◽  
State Formula ◽  
The Masses ◽  
The Magnetic Field

The mass modifications of the open charm ([Formula: see text] and [Formula: see text]) mesons, and their effects on the decay widths [Formula: see text] as well as of the charmonium state, [Formula: see text] to open charm mesons ([Formula: see text]), are investigated in the presence of strong magnetic fields. These are studied accounting for the mixing of the pseudoscalar ([Formula: see text]) and vector ([Formula: see text]) mesons ([Formula: see text], [Formula: see text] mixings), with the mixing parameter, [Formula: see text] of a phenomenological three-point ([Formula: see text]) vertex interaction determined from the observed radiative decay width of [Formula: see text]. For charged [Formula: see text] mixing, this parameter is dependent on the magnetic field, because of the Landau level contributions to the vacuum masses of these mesons. The masses of the charged [Formula: see text] and [Formula: see text] mesons modified due to [Formula: see text] mixing, in addition, have contributions from the lowest Landau levels in the presence of a strong magnetic field. The effects of the magnetic field on the decay widths are studied using a field theoretical model of composite hadrons with quark (and antiquark) constituents. The matrix elements for these decays are evaluated using the light quark–antiquark pair creation term of the free Dirac Hamiltonian for the constituent quark field, with explicit constructions for the charmonium state [Formula: see text], the open charm ([Formula: see text], [Formula: see text], [Formula: see text]) mesons and the pion states in terms of the constituent quark fields. The parameter for the charged [Formula: see text] mixing is observed to increase appreciably with increase in the magnetic field. This leads to dominant modifications to their masses, and hence the decay widths of charged [Formula: see text] as well as [Formula: see text] at large values of the magnetic field. The modifications of the masses and decay widths of the open and hidden charm mesons in the presence of strong magnetic fields should have observable consequences on the production of the open charm ([Formula: see text] and [Formula: see text]) mesons as well as of the charmonium states resulting from noncentral ultra-relativistic heavy ion collision experiments.

scholarly journals Oscillatory convection in strong magnetic fields and origin of active regions

1968 ◽  
Vol 35 ◽  
pp. 127-130 ◽  
Author(s):  
S. I. Syrovatsky ◽  
Y. D. Zhugzhda
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Active Regions ◽  
Oscillatory Convection ◽  
Strong Magnetic Fields ◽  
Various Boundary Conditions ◽  
Convective Cells ◽  
The Magnetic Field ◽  
Polytropic Atmosphere

The convection in a compressible inhomogeneous conducting fluid in the presence of a vertical uniform magnetic field has been studied. It is shown that a new mode of oscillatory convection occurs, which exists in arbitrarily strong magnetic fields. The convective cells are stretched along the magnetic field, their horizontal dimensions are determined by radiative cooling. Criteria for convective instability in a polytropic atmosphere are obtained for various boundary conditions in the case when the Alfvén velocity is higher compared with the velocity of sound.The role of oscillatory convection in the origin of sunspots and active regions is discussed.

STABILITY OF DEUTERONS IN STRONG MAGNETIC FIELDS: AN EXACTLY SOLVED MODEL

1988 ◽  
Vol 03 (04) ◽  
pp. 345-351 ◽  
Author(s):  
M. MOSHINSKY ◽  
G. LOYOLA
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Triplet State ◽  
Strong Magnetic Field ◽  
Canonical Transformation ◽  
Singlet State ◽  
Oscillator Potential ◽  
Strong Magnetic Fields ◽  
Expectation Value ◽  
The Magnetic Field

We consider the nucleons in the triplet state of the deuteron bound by an oscillator potential and in a strong magnetic field. Using an appropriate linear canonical transformation, we solve the problem exactly. The expectation value of the distance between the nucleons in the plane perpendicular to the magnetic field diminishes slowly as we increase the latter, which suggests that the triplet state of the deuteron is stable. The conclusion is not altered when we consider possible transitions from the triplet to the singlet state due to the action of the magnetic field on the spins.

scholarly journals Modified Adiabatic Approximation for A Hydrogen Atom Moving in A Magnetic Field

1994 ◽  
Vol 147 ◽  
pp. 555-559
Author(s):  
V.G. Bezchastnov ◽  
A.Y. Potekhin
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Magnetic Fields ◽  
Density Distribution ◽  
Cross Sections ◽  
Electron Density Distribution ◽  
Adiabatic Approximation ◽  
Strong Magnetic Fields ◽  
Radiative Transitions ◽  
The Magnetic Field

AbstractMotion of a hydrogen atom across the magnetic field shifts center of electron density distribution. For strong magnetic fields, the radiative transitions can be considered in the modified adiabatic approximation in which the shifts are taken into account. The method is illustrated by calculating the photoionization cross sections.

NEUTRINOS IN EXTREMELY STRONG MAGNETIC FIELDS

2000 ◽  
Vol 15 (04) ◽  
pp. 523-534
Author(s):  
A. PÉREZ MARTÍNEZ ◽  
H. PÉREZ ROJAS ◽  
D. OLIVA AGÜERO ◽  
A. AMÉZAGA HECHAVARRÍA ◽  
S. RODRÍGUEZ ROMO
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Threshold Energy ◽  
Strong Magnetic Fields ◽  
Self Energy ◽  
Loop Approximation ◽  
The One ◽  
The Magnetic Field ◽  
Thermal Background

We compute the dispersion curves for neutrinos propagating in a very dense electroweak plasma, in magnetic fields of order [Formula: see text]. The neutrino self-energy is calculated in the one-loop approximation. The dispersion equation is solved for motion parallel and perpendicular to the external magnetic field. We obtain an effective neutrino mass which increases with the magnetic field, up to values B where threshold energy for creation of W± pairs (out from the thermal background) is reached.

scholarly journals EFFECT OF STRONG MAGNETIC FIELDS ON THE EQUILIBRIUM OF A DEGENERATE GAS OF NUCLEONS AND ELECTRONS

1996 ◽  
Vol 10 (23) ◽  
pp. 1141-1149 ◽  
Author(s):  
CHOON-LIN HO ◽  
V.R. KHALILOV ◽  
CHI YANG
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Strong Magnetic Field ◽  
Constant Magnetic Field ◽  
Fermi Momentum ◽  
Magnetic Field Induction ◽  
Strong Magnetic Fields ◽  
Field Induction ◽  
The Magnetic Field

We obtain the equations that define the equilibrium of a homogeneous relativistic gas of neutrons, protons and electrons in a constant magnetic field as applied to the conditions that probably occur near the center of neutron stars. We compute the relative densities of the particles at equilibrium and the Fermi momentum of electrons in the strong magnetic field as function of the density of neutrons and the magnetic field induction. Novel features are revealed as to the ratio of the number of protons to the number of neutrons at equilibrium in the presence of large magnetic fields.

scholarly journals Revisiting quark stars under the influence of strong magnetic fields

2012 ◽  
Vol 8 (S291) ◽  
pp. 458-458
Author(s):  
Debora Menezes
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Quark Matter ◽  
Mean Field ◽  
Heavy Ion ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Solar Mass ◽  
Strong Magnetic Fields ◽  
The Masses

AbstractQuark matter at finite temperature and subject to strong magnetic fields is possibly present in the early stages of heavy ion collisions and in the interior of protoneutron stars. We use the mean field approximation to investigate this type of quark matter described by the Nambu–Jona-Lasinio model. The energy per baryon of magnetized quark matter becomes more bound than nuclear matter made of iron nuclei, for magnetic fields around 1019 G. When the su(3) NJL model is applied to stellar matter, the maximum mass configurations are always above 1.45 solar masses and may be as high as 1.9 solar masses for a central magnetic field of 1018 G. These numbers are within the masses of observed neutron stars but exclude the recently measured star with 1.97 solar mass.The effect of the magnetic field on the effective quark masses and chemical potentials is only felt for quite strong magnetic fields, above 5 × 1018 G, with larger effects for the lower densities. Spin polarizations are more sensitive to weaker magnetic fields and are larger for lower temperatures and lower densities.

scholarly journals Strong magnetic fields in bipolar outflows

1991 ◽  
Vol 147 ◽  
pp. 373-376
Author(s):  
M. D. Smith ◽  
P. W. J. L. Brand ◽  
A. Moorhouse
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Molecular Hydrogen ◽  
Active Regions ◽  
Young Star ◽  
Molecular Gas ◽  
Bipolar Outflows ◽  
Strong Magnetic Fields ◽  
Bow Shocks ◽  
The Magnetic Field

A supersonic wind from a young star will produce regions of strong magnetic field in the stellar environment. The associated shocks compress the molecular gas, increasing the density n, pressure p, and field B. Crucially, the Alfvén speed, vA∝ B/n1/2, is also increased since the total shock compression is approximately of the form B ∝ n. But is there any evidence for such high vA- or ‘active cloud’ - regions within bipolar outflows? We indicate below one implication which has important observable consequences: fast shocks of low Alfvén number (v/vA) now arise. With a low ionization level, the C-shock structure is qualitatively different from the high Alfvén number flows which are common to ‘quiescent cloud’ conditions. The magnetic-field cushioning now allows molecular hydrogen to survive very fast shocks and broad H2 lines are feasible. We display results which show that the resolved broad lines and line ratio properties in the OMC-1 outflow can be explained with fast bow shocks moving through such active regions.

scholarly journals Pulsation of magnetic stars

2013 ◽  
Vol 9 (S301) ◽  
pp. 197-204 ◽  
Author(s):  
Hideyuki Saio
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Amplitude Distribution ◽  
High Order ◽  
Frequency Separation ◽  
Strong Magnetic Fields ◽  
Magnetic Stars ◽  
Ap Stars ◽  
The Magnetic Field ◽  
Large Frequency

AbstractSome Ap stars with strong magnetic fields pulsate in high-order p modes; they are called roAp (rapidly oscillating Ap) stars. The p-mode frequencies are modified by the magnetic fields. Although the large frequency separation is hardly affected, small separations are modified considerably. The magnetic field also affects the latitudinal amplitude distribution on the surface. We discuss the properties of axisymmetric p-mode oscillations in roAp stars.

scholarly journals NEUTRON SPIN POLARIZATION IN STRONG MAGNETIC FIELDS

2005 ◽  
Vol 14 (08) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. WEN ◽  
L. S. KISSLINGER ◽  
WALTER GREINER ◽  
G. MAO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spin Polarization ◽  
Magnetic Moments ◽  
Wave Functions ◽  
Neutron Spin ◽  
Strong Magnetic Fields ◽  
Protons And Neutrons ◽  
Free Fermi ◽  
The Magnetic Field

The effects of strong magnetic fields on the inner crust of neutron stars are investigated after taking into account the anomalous magnetic moments of nucleons. The energy spectra and wave functions for protons and neutrons in a uniform magnetic field are provided. The particle spin polarizations and the yields of protons and neutrons are calculated in a free Fermi gas model. Obvious spin polarizations occur when B≥1014 G for protons and B≥1017 G for neutrons, respectively. It is shown that the neutron spin polarization depends solely on the magnetic field strength.

scholarly journals The change of resistance of gold crystals at very low temperatures in a magnetic field and supra-conductivity

1930 ◽  
Vol 126 (803) ◽  
pp. 683-695 ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Low Temperatures ◽  
Crystalline State ◽  
Specific Resistance ◽  
Systematic Research ◽  
Continuous Curve ◽  
Strong Magnetic Fields ◽  
Relative Change ◽  
The Magnetic Field

In a paper published last year the author described a systematic research on the change of resistance which occurs in a number of metals in strong magnetic fields. As a result of these investigations the following formulæ expressing the relative change of resistance ∆R/R o with the field H were found to hold :— ∆R/R o = β' H 2 /3H k H ≼ H k , (1) and ∆R/R o = β' ( H-H k +H k 2 /3H) H ≽ H k , (2) where β' and H k are constant for a given sample of a metal and at a given temperature. These two expressions form a continuous curve, and it is evident that the formula (1) which holds for the weaker fields, shows that the resistance increases as the square of H, and formula (2) indicates that the change of resistance in strong fields approaches a linear law. These two formulæ have been obtained mathematically on the following assumption. It is known that in a metal which is not in a perfect crystalline state, and which contains even small traces of impurities, there exists a disturbance which increases its specific resistance. My hypothesis was that a magnetic field increases the specific resistance in a similar way to these imperfections, so that they are equivalent to an internal magnetic field H k , orientated at random. Then, if the metal is brought under the influence of an outside magnetic field H, the increase of resistance is such as would be produced by a combination of the two fields. Further, I assumed that the increase of resistance is proportional to the magnetic field, and this led to formulæ (1) and (2) which appear to fit all my experimental results very well. Several important consequences follow from this hypothesis.

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