9,101 research outputs found
The Higgs Sector of the Minimal 3 3 1 Model Revisited
The mass spectrum and the eigenstates of the Higgs sector of the minimal 3 3
1 model are revisited in detail. There are discrepancies between our results
and previous results by another author.Comment: 20 pages, latex, two figures. One note and one reference are adde
Evolution of Nuclear Shell Structure due to the Pion Exchange Potential
The evolution of nuclear shell structure is investigated for the first time
within density-dependent relativistic Hartree-Fock theory and the role of
-exchange potential is studied in detail. The energy differences between
the neutron orbits \Lrb{\nu1h_{9/2},\nu 1i_{13/2}} in the N=82 isotones and
between the proton ones \Lrb{\pi1g_{7/2},\pi1h_{11/2}} in the Z=50 isotopes
are extracted as a function of neutron excess . A kink around for
the N=82 isotones is found as an effect resulting from pion correlations. It is
shown that the inclusion of -coupling plays a central role to provide
realistic isospin dependence of the energy differences. In particular, the
tensor part of the -coupling has an important effect on the characteristic
isospin dependence observed in recent experiments.Comment: 4 pages and 4 figure
Carbon Border Adjustment Mechanism Impact Assessment Report for Vietnam
The EU’s Carbon Border Adjustment Mechanism (CBAM) is evolving rapidly, with many uncertainties remaining regarding its long-term scope, embedded emissions calculation, and reactions of EU-trade partners. In its current form, the CBAM can affect Vietnamese enterprises exporting to EU although its direct impacts on Vietnam’s GDP are unlikely significant. If the CBAM is expanded to other trade-intensive sectors of Vietnam or taken up by other key trading partners of Vietnam, the impacts may grow quickly. Therefore, Vietnam should engage proactively with the CBAM and prepare for mitigation of potential impacts. One of the pro-active approaches is to accelerate and deepen the adoption of carbon pricing. This will facilitate energy transition, support achievement of Vietnam’s climate change mitigation target (NDC) under the Paris Agreement and long-term net-zero targets and would allow to harness co-benefits. It is also advisable for Vietnam to engage in constructive dialogues with the EU in order to negotiate a fair implementation of CBAM that takes into account Vietnam’s efforts. A key demand here should be the use of emissions credits instead of having to buy CBAM certificates
Relativistic Hartree-Fock-Bogoliubov theory with Density Dependent Meson-Nucleon Couplings
Relativistic Hartree-Fock-Bogoliubov (RHFB) theory with density-dependent
meson-nucleon couplings is presented. The integro-differential RHFB equations
are solved by expanding the different components of the quasi-particle spinors
in the complete set of eigen-solutions of the Dirac equations with Woods-Saxon
potentials. Using the finite-range Gogny force D1S as an effective interaction
in the pairing channel, systematic RHFB calculations are performed for Sn
isotopes and N=82 isotones. It is demonstrated that an appropriate description
of both mean field and pairing effects can be obtained within RHFB theory with
finite range Gogny pairing forces. Better systematics are also found in the
regions from the stable to the neutron-rich side with the inclusion of Fock
terms, especially in the presence of -tensor couplings.Comment: 11 pages, 2 tables and 4 figure
New effective interactions in RMF theory with non-linear terms and density-dependent meson-nucleon coupling
New parameter sets for the Lagrangian density in the relativistic mean field
(RMF) theory, PK1 with nonlinear sigma- and omega-meson self-coupling, PK1R
with nonlinear sigma-, omega- and rho-meson self-coupling and PKDD with the
density-dependent meson-nucleon coupling, are proposed. They are able to
provide an excellent description not only for the properties of nuclear matter
but also for the nuclei in and far from the valley of beta-stability. For the
first time in the parametrization of the RMF Lagrangian density, the
center-of-mass correction is treated by a microscopic way, which is essential
to unify the description of nuclei from light to heavy regions with one
effective interaction.Comment: 22 pages, 16 EPS figures, RevTeX
Spin symmetry in Dirac negative energy spectrum in density-dependent relativistic Hartree-Fock theory
The spin symmetry in the Dirac negative energy spectrum and its origin are
investigated for the first time within the density-dependent relativistic
Hartree-Fock (DDRHF) theory. Taking the nucleus O as an example, the
spin symmetry in the negative energy spectrum is found to be a good
approximation and the dominant components of the Dirac wave functions for the
spin doublets are nearly identical. In comparison with the relativistic Hartree
approximation where the origin of spin symmetry lies in the equality of the
scalar and vector potentials, in DDRHF the cancellation between the Hartree and
Fock terms is responsible for the better spin symmetry properties and
determines the subtle spin-orbit splitting. These conclusions hold even in the
case when significant deviations from the G-parity values of the
meson-antinucleon couplings occur.Comment: 13 pages, 7 figures, 1 table, accepted by Eur. Phys. J.
The relationship between sedentary behavior and dry eye disease
Purpose: Sedentary behavior (SB) has been linked with low-grade systemic inflammation, which could play a role in the development of dry eye disease (DED). This cross-sectional study aims to investigate the association between SB and DED. Methods: We assessed 48,418 participants from the population-based Lifelines cohort (58% female, 18–96 years). Women's Health Study (WHS)-defined DED was the primary outcome. SB was assessed using the Marshall Sitting Questionnaire. The relationship between DED and SB was analyzed using logistic regressions, corrected for age, sex, BMI, smoking status, demographics, and 48 comorbidities. Any potential modifying effect of physical activity (PA) was also assessed, and the analyses were repeated excluding the most computer-intensive domains, investigating SB independent from screen exposure. Results: WHS-defined DED was present in 9.1% of participants. Greater SB was associated with an increased risk of DED (odds ratio (OR) 1.015 per hour/day, 95%CI 1.005–1.024, P = 0.004). The association between SB and DED was only significant for those with less than WHO-recommended PA (OR 1.022, 95%CI 1.002–1.042, P = 0.027), and not in participants meeting WHO's recommendation (OR 1.011, 95%CI 0.999–1.023, P = 0.076). Lastly, when excluding computer-related sitting, the relationship between SB and DED was attenuated, and no longer significant (OR 1.009, 95%CI 0.996–1.023, P = 0.19). Conclusions: Greater sedentary time was tied to an increased risk of DED, especially for those with lower PA levels than WHO recommendations. However, as there was no significant association when computer-intensive sitting time was excluded, screen use could explain the observed relationship and should be noted as a possible key confounder.</p
On Dirac Factorization, Fractional Calculus, and Polynomial Linearization
We postulate the existence of fractional order derivative operators that
satisfy a semi-group property in order to further factor the Klein-Gordon
equation in Dirac's fashion. The analog of Dirac's matrices are found and we
study the generalization of the Dirac algebra generated by these matrices. In
this way, a hierarchy of generalized Clifford algebras is formed. We then apply
this procedure to Schr\"odinger's equation, and examine the resulting
coefficients before moving to a more general setting in which we study the
linearization of polynomials with coefficients that do not commute with the
indeterminates. Partial differential equations with non-constant coefficients
are the archetypal example in this setting.Comment: 15 page
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