1,536 research outputs found
Mass matrices and eigenstates for scalars / pseudoscalars; indirect CP violation, mass hierarchies and symmetry breaking
Get PDFI study indirect CP violation for neutral kaons, and extend it to large
values of the CP-violating parameter (taken to be real). I show how and at
which condition there can exist a continuous set of basis in which the kinetic
and mass terms in the Lagrangian can be diagonalized simultaneously. An
ambiguity results for the mass spectrum, which then depends on the basis. In
particular, for fixed (positive) (mass)^2 of the CP eigenstates K^0_1, K^0_2,
and for certain ranges of values of the CP-violating parameter, a negative
(mass)^2 can arise in the CP-violating basis. Under certain conditions, even a
small perturbation, by lifting the ambiguity, can strongly alter the pattern of
masses. These investigations extend in a natural way to indirect CP violation
among a set of Higgs-like doublets. The C-odd commutator [K^0, K^0 bar], or its
equivalent for Higgs multiplets, plays an important role. The condition for its
vanishing and its consequences are among the main concerns of this work.Comment: LaTeX2e, 35 pages, 10 postscript figures + 1 log
Binary systems of neutral mesons in Quantum Field Theory
Full text linkQuasi-degenerate binary systems of neutral mesons of the kaon type are
investigated in Quantum Field Theory (QFT). General constraints cast by
analyticity and discrete symmetries P, C, CP, TCP on the propagator (and on its
spectral function) are deduced. Its poles are the physical masses; this
unambiguously defines the propagating eigenstates. It is diagonalized and its
spectrum thoroughly investigated. The role of ``spurious'' states, of zero norm
at the poles, is emphasized, in particular for unitarity and for the
realization of TCP symmetry. The K_L-K_S mass splitting triggers a tiny
difference between their CP violating parameters \epsilon_L and \epsilon_S,
without any violation of TCP. A constant mass matrix like used in Quantum
Mechanics (QM) can only be introduced in a linear approximation to the inverse
propagator, which respects its analyticity and positivity properties; it is
however unable to faithfully describe all features of neutral mesons as we
determine them in QFT, nor to provide any sensible parameterization of eventual
effects of TCP violation. The suitable way to diagonalize the propagator makes
use of a bi-orthogonal basis; it is inequivalent to a bi-unitary transformation
(unless the propagator is normal, which cannot occur here). Problems linked
with the existence of different ``in'' and ``out'' eigenstates are smoothed
out. We study phenomenological consequences of the differences between the QFT
and QM treatments. The non-vanishing of semi-leptonic asymmetry \delta_S -
\delta_L does not signal, unlike usually claimed, TCP violation, while A_TCP
keeps vanishing when TCP is realized. We provide expressions invariant by the
rephasing of K0 and K0bar.Comment: 44 pages, 2 figures. Version to appear in Int. J. Mod. Phys.
Next-to-MLLA corrections to single inclusive kt-distributions and 2-particle correlations in a jet
Get PDFThe hadronic kt-spectrum inside a high energy jet is determined including
corrections of relative magnitude O{\sqrt{\alpha_s}} with respect to the
Modified Leading Logarithmic Approximation (MLLA), in the limiting spectrum
approximation (assuming an infrared cut-off Q0 =Lambda_{QCD}) and beyond
Q_0\ne\Lambda_{QCD}. The results in the limiting spectrum approximation are
found to be, after normalization, in impressive agreement with preliminary
measurements by the CDF collaboration, unlike what occurs at MLLA, pointing out
small overall non-perturbative contributions. Within the same framework,
2-particle correlations inside a jet are also predicted at NMLLA and compared
to previous MLLA calculations.Comment: 35 pages and 39 figures. Comments, appendices, figures, references
added. Version to appear in Phys. Rev.
Modification of Coulomb law and energy levels of the hydrogen atom in a superstrong magnetic field
Get PDFWe obtain the following analytical formula which describes the dependence of
the electric potential of a point-like charge on the distance away from it in
the direction of an external magnetic field B: \Phi(z) = e/|z| [ 1-
exp(-\sqrt{6m_e^2}|z|) + exp(-\sqrt{(2/\pi) e^3 B + 6m_e^2} |z|) ]. The
deviation from Coulomb's law becomes essential for B > 3\pi B_{cr}/\alpha = 3
\pi m_e^2/e^3 \approx 6 10^{16} G. In such superstrong fields, electrons are
ultra-relativistic except those which occupy the lowest Landau level (LLL) and
which have the energy epsilon_0^2 = m_e^2 + p_z^2. The energy spectrum on which
LLL splits in the presence of the atomic nucleus is found analytically. For B >
3 \pi B_{cr}/\alpha, it substantially differs from the one obtained without
accounting for the modification of the atomic potential.Comment: version to be published in Physical Review D (incorrect "Keywords" in
previous version have been cancelled
Undergraduate Student’s Perceptions of Factors that Enable and Inhibit their Professional Skill Development
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The Schnitzler syndrome
Get PDFThe Schnitzler syndrome is a rare and underdiagnosed entity which is considered today as being a paradigm of an acquired/late onset auto-inflammatory disease. It associates a chronic urticarial skin rash, corresponding from the clinico-pathological viewpoint to a neutrophilic urticarial dermatosis, a monoclonal IgM component and at least 2 of the following signs: fever, joint and/or bone pain, enlarged lymph nodes, spleen and/or liver, increased ESR, increased neutrophil count, abnormal bone imaging findings. It is a chronic disease with only one known case of spontaneous remission. Except of the severe alteration of quality of life related mainly to the rash, fever and pain, complications include severe inflammatory anemia and AA amyloidosis. About 20% of patients will develop a lymphoproliferative disorder, mainly Waldenström disease and lymphoma, a percentage close to other patients with IgM MGUS. It was exceedingly difficult to treat patients with this syndrome until the IL-1 receptor antagonist anakinra became available. Anakinra allows a complete control of all signs within hours after the first injection, but patients need continuous treatment with daily injections
Inclusive teaching practices: a comparative case study of integrated inclusion in different contexts
Full text linkOn the Khalfin's improvement of the LOY effective Hamiltonian for neutral meson complex
Full text linkThe general properties of the effective Hamiltonian for neutral meson system
improved by L.A. Khalfin in 1980 are studied. It is shown that contrary to the
standard result of the Lee--Oehme--Yang (LOY) theory, the diagonal matrix
elements of this effective Hamiltonian can not be equal in a CPT invariant
system. It is also shown that the scalar product of short, , and long,
, living superpositions of neutral kaons can not be real when CPT
symmetry is conserved in the system under considerations whereas within the LOY
theory such a scalar product is real.Comment: LaTeX2e, 25 pages, new comment and references adde
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