926 research outputs found
CPT and Quantum Mechanics Tests with Kaons: Theory
In this talk I review theoretical motivations for possible CPT Violation and
deviations from ordinary quantum mechanical behavior of field theoretic systems
in some quantum gravity models, and I describe the relevant precision tests
using neutral and charged Kaons. I emphasize the possibly unique role of
neutral-meson factories in providing specific tests of models in which the CPT
operator is not well-defined, leading to modifications of
Einstein-Podolsky-Rosen (EPR) particle correlators.Comment: Invited talk at BEACH2006 Conference (Lancaster Univ., UK, July 2-8
2006), 4 pages LaTeX, 2 eps figures incorporate
Cosmological Constant and Local Gravity
We discuss the linearization of Einstein equations in the presence of a
cosmological constant, by expanding the solution for the metric around a flat
Minkowski space-time. We demonstrate that one can find consistent solutions to
the linearized set of equations for the metric perturbations, in the Lorentz
gauge, which are not spherically symmetric, but they rather exhibit a
cylindrical symmetry. We find that the components of the gravitational field
satisfying the appropriate Poisson equations have the property of ensuring that
a scalar potential can be constructed, in which both contributions, from
ordinary matter and , are attractive. In addition, there is a
novel tensor potential, induced by the pressure density, in which the effect of
the cosmological constant is repulsive. We also linearize the Schwarzschild-de
Sitter exact solution of Einstein's equations (due to a generalization of
Birkhoff's theorem) in the domain between the two horizons. We manage to
transform it first to a gauge in which the 3-space metric is conformally flat
and, then, make an additional coordinate transformation leading to the Lorentz
gauge conditions. We compare our non-spherically symmetric solution with the
linearized Schwarzschild-de Sitter metric, when the latter is transformed to
the Lorentz gauge, and we find agreement. The resulting metric, however, does
not acquire a proper Newtonian form in terms of the unique scalar potential
that solves the corresponding Poisson equation. Nevertheless, our solution is
stable, in the sense that the physical energy density is positive.Comment: 7 pages revtex, no figures; discussion on light bending added, no
effect on conclusions, version to appear in Physical Review D
The signal of ill-defined CPT weakening entanglement in the system
In the presence of quantum gravity fluctuations (space-time foam), the CPT
operator may be ill-defined. Its perturbative treatment leads to a modification
of the Einstein-Podolsky-Rosen correlation of the neutral meson system by
adding an Entanglement-weakening term of the wrong exchange symmetry, the
-effect. In the current paper we identify how to probe the complex
in the entangled -system using Flavour(f)-CP(g) eigenstate decay
channels: the connection between the Intensities for the two time-ordered
decays (f, g) and (g, f) is lost. Appropriate observables are constructed
allowing independent experimental determinations of Re() and
Im(), disentangled from CPT violation in the evolution Hamiltonian
Re() and Im(). 2- tensions for both Re() and
Im() are shown to be uncorrelated.Comment: 18 pages, 4 figures, 1 tabl
METing SUSY on the Z peak
Recently the ATLAS experiment announced a 3 excess at the Z-peak
consisting of 29 pairs of leptons together with two or more jets, GeV and GeV, to be compared with
expected lepton pairs in the Standard Model. No excess outside the Z-peak was
observed. By trying to explain this signal with SUSY we find that only
relatively light gluinos, TeV, together with a
heavy neutralino NLSP of GeV decaying
predominantly to Z-boson plus a light gravitino, such that nearly every gluino
produces at least one Z-boson in its decay chain, could reproduce the excess.
We construct an explicit general gauge mediation model able to reproduce the
observed signal overcoming all the experimental limits. Needless to say, more
sophisticated models could also reproduce the signal, however, any model would
have to exhibit the following features, light gluinos, or heavy particles with
a strong production cross-section, producing at least one Z-boson in its decay
chain. The implications of our findings for the Run II at LHC with the scaling
on the Z peak, as well as for the direct search of gluinos and other SUSY
particles, are pointed out.Comment: 24 pages, 17 figures, simulation improved, Checkmate analysis added,
new benchmark point included. Typos corrected, conclusions unchange
CPT and Quantum Mechanics Tests with Kaons
In this review we first discuss the theoretical motivations for possible CPT
violation and deviations from ordinary quantum-mechanical behavior of
field-theoretic systems in the context of an extended class of quantum-gravity
models. Then we proceed to a description of precision tests of CPT symmetry
using mainly neutral kaons. We emphasize the possibly unique role of neutral
meson factories in providing specific tests of models where the
quantum-mechanical CPT operator is not well-defined, leading to modifications
of Einstein-Podolsky-Rosen particle correlators. Finally, we present tests of
CPT, T, and CP using charged kaons, and in particular K_l4 decays, which are
interesting due to the high statistics attainable in experiments.Comment: Invited contribution to DAFNE Physics Handbook, 23 pages LaTeX, 9 eps
figures incorporate
IGR J19294+1816: a new Be-X ray binary revealed through infrared spectroscopy
The aim of this work is to characterize the counterpart to the INTEGRAL High
Mass X-ray Binary candidate IGR J19294+1816 so as to establish its true nature.
We obtained H band spectra of the selected counterpart acquired with the NICS
instrument mounted on the Telescopio Nazionale Galileo (TNG) 3.5-m telescope
which represents the first infrared spectrum ever taken of this source. We
complement the spectral analysis with infrared photometry from UKIDSS, 2MASS,
WISE and NEOWISE databases. We classify the mass donor as a Be star.
Subsequently, we compute its distance by properly taking into account the
contamination produced by the circumstellar envelope. The findings indicate
that IGR J19294+1816 is a transient source with a B1Ve donor at a distance of
kpc, and luminosities of the order of erg s,
displaying the typical behaviour of a Be X-ray binary.Comment: 8 pages, 6 figures, accepted to be published in MNRA
T and CPT Symmetries in Entangled Neutral Meson Systems
Genuine tests of an asymmetry under T and/or CPT transformations imply the
interchange between in-states and out-states. I explain a methodology to
perform model-indepedent separate measurements of the three CP, T and CPT
symmetry violations for transitions involving the decay of the neutral meson
systems in B- and {\Phi}-factories. It makes use of the quantum-mechanical
entanglement only, for which the individual state of each neutral meson is not
defined before the decay of its orthogonal partner. The final proof of the
independence of the three asymmetries is that no other theoretical ingredient
is involved and that the event sample corresponding to each case is different
from the other two. The experimental analysis for the measurements of these
three asymmetries as function of the time interval {\Delta}t > 0 between the
first and second decays is discussed, as well as the significance of the
expected results. In particular, one may advance a first observation of true,
direct, evidence of Time-Reserval-Violation in B-factories by many standard
deviations from zero, without any reference to, and independent of,
CP-Violation. In some quantum gravity framework the CPT-transformation is
ill-defined, so there is a resulting loss of particle-antiparticle identity.
This mechanism induces a breaking of the EPR correlation in the entanglement
imposed by Bose statistics to the neutral meson system, the so-called
{\omega}-effect. I present results and prospects for the {\omega}-parameter in
the correlated neutral meson-antimeson states.Comment: Proc. DISCRETE 2010, Symposium on Prospects in the Physics of
Discrete Symmetries, December 2010, Rom
CPT violation in entangled B0-B0bar states and the demise of flavour tagging
We discuss the demise of flavour tagging due to the loss of the
particle-antiparticle identity of neutral B-mesons in the
Einstein-Podolsky-Rosen correlated states. Such a situation occurs in cases
where the CPT operator is ill-defined, as happens, for example, in quantum
gravity models with induced decoherence in the matter sector. The time
evolution of the perturbed B0-B0bar initial state, as produced in B-factories,
is sufficient to generate new two-body states. For flavour specific decays at
equal times, we discuss two definite tests of the two body entanglement: (i)
search for the would-be forbidden B0 B0 and B0bar B0bar states; (ii) deviations
from the indistinguishable probability between the permuted states B0bar B0 and
B0 B0bar.Comment: 12 pages LATEX, one eps figure incorporate
Probing CPT in transitions with entangled neutral kaons
In this paper we present a novel CPT symmetry test in the neutral kaon system based, for the first time, on the direct comparison of the probabilities of a transition and its CPT reverse. The required interchange of in out states for a given process is obtained exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs produced at a phi-factory. The observable quantities have been constructed by selecting the two semileptonic decays for flavour tag, the pi and 3 pi(0) decays for CP tag and the time orderings of the decay pairs. The interpretation in terms of the standard Weisskopf-Wigner approach to this system, directly connects CPT violation in these observables to the violating R delta parameter in the mass matrix of K-0 (K) over bar (0), a genuine CPT violating effect independent of Delta Gamma and not requiring the decay as an essential ingredient. Possible spurious effects induced by CP violation in the decay and/or a violation of the Delta S = Delta Q rule have been shown to be well under control. The proposed test is thus fully robust, and might shed light on possible new CPT violating mechanisms, or further improve the precision of the present experimental limits. It could be implemented at the DA Phi NE facility in Frascati, where the KLOE-2 experiment might reach a statistical sensitivity of O (10(-3)) on the newly proposed observable quantities
QCD Accurately Predicts the Induced Pseudoscalar Coupling Constant
Using chiral Ward identities of QCD, we derive a relation for the induced
pseudoscalar coupling constant which is accurate within a few percent, .Comment: 5pp, LaTeX, CRN-94/1
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