scholarly journals Dirac confinement of a heavy quark-light quark system (Q,q̄) in high orbital angular momentum states

1998 ◽  
Author(s):  
M. A. Avila
Keyword(s):  
Angular Momentum ◽  
Heavy Quark ◽  
Orbital Angular Momentum ◽  
Light Quark ◽  
Quark System

DIQUARK FORMATION IN ANGULAR-MOMENTUM-EXCITED BARYONS

2009 ◽  
Vol 24 (10) ◽  
pp. 1987-1994 ◽  
Author(s):  
ANTONIO CARLOS BAPTISTA ANTUNES ◽  
LEILA JORGE ANTUNES
Keyword(s):  
Angular Momentum ◽  
Heavy Quark ◽  
Potential Barrier ◽  
Light Quark ◽  
Heavy Quarks ◽  
Centrifugal Barrier ◽  
Large Angular Momentum

Diquarks, or metastable clusters of two quarks inside baryons, are shown to be produced by angular momentum excitation. In baryons with a light quark and two heavy quarks with large angular momentum (L>2), the centrifugal barrier that appears in the rotation frame of the two heavy quarks prevents the light quark from passing freely between the two heavy quarks. The light quark must tunnelize through this potential barrier, which gives rise to the clusters of a light and a heavy quark.

SOLUTIONS OF A DIRAC HYDROGENLIKE MESON AND SCALAR CONFINEMENT AT LOW ORBITAL ANGULAR MOMENTUM STATES

1999 ◽  
Vol 14 (11) ◽  
pp. 1703-1710
Author(s):  
M. A. AVILA
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Light Quark ◽  
Relativistic Effects ◽  
Wave Functions ◽  
Confinement Potential ◽  
Relativistic Corrections ◽  
Lorentz Scalar ◽  
Dirac Hamiltonian

Wave functions of a heavy-light quark [Formula: see text] system described by a covariant Dirac Hamiltonian are analyzed. By assuming that the confinement potential is a Lorentz scalar (S), the slope of the Isgur–Wise function is calculated at zero recoil point. The result obtained is ξ′(1)= -0.93± 0.05. This means that the solutions are perfectly consistent. If relativistic corrections in the light quark wave functions are included the result is ξ′(1)=-1.01± 0.04. From heavy-light data this suggests that if relativistic effects are considered, scalar confinement is reliable in low orbital angular momentum states.

LIGHT QUARK ORBITAL RADIUS OF A HEAVY QUARK–LIGHT QUARK SYSTEM IN AN S-STATE

1999 ◽  
Vol 14 (02) ◽  
pp. 113-124
Author(s):  
M. A. AVILA
Keyword(s):  
Heavy Quark ◽  
Quark Mass ◽  
Light Quark ◽  
Effective Theory ◽  
Heavy Quark Effective Theory ◽  
Expectation Value ◽  
Maximum Value ◽  
Inertia Parameter ◽  
Light Quark Mass ◽  
Quark System

Radial probability density function of a heavy quark–light quark [Formula: see text] system in an S-state is analyzed numerically. It is found that the maximum of this function at r=a0 and the light quark energy (Eq) are related through the relation Eq=Z/a0, where Z=c0/c, c is the strength of the color Coulomb potential and c0=0.446. Z<1 can be thought of as due to a color anti-screening effect. The respective expectation value for r in this state is [Formula: see text]. These results are valid for c in the range c0≤ c≤0.7 and a light quark mass in the range 0≤ m≤ 300 MeV. As a result of these patterns of regularity, bounds on the mass of the heavy quarks are imposed. These give mc=1.3±0.33 GeV and mb=4.6±0.3 GeV. It is also shown that Eq is not directly an "inertia" parameter, as it has been called by the heavy quark effective theory, but a physical quantity that needs to be measured. The relations found in the present work coincide with the maximum value that the slope of the Isgur–Wise function at zero recoil can take, in either way [Formula: see text] or [Formula: see text].

Advanced Mode Unity Using Loop Antennas Proximate to Reflector for Orbital Angular Momentum Communication

2018 ◽  
Author(s):  
Ryohei Yamagishi ◽  
Hiroto Otsuka ◽  
Ryo Ishikawa ◽  
Akira Saitou ◽  
Hiroshi Suzuki ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Loop Antennas

Highly dispersive coupled ring-core fiber for orbital angular momentum modes

2020 ◽  
Vol 117 (19) ◽  
pp. 191101
Author(s):  
Wenpu Geng ◽  
Yiqiao Li ◽  
Yuxi Fang ◽  
Yingning Wang ◽  
Changjing Bao ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Core Fiber ◽  
Ring Core

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

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