Rotation-invariant relations in vector meson decays into fermion pairs

The rotational properties of angular momentum eigenstates imply the existence of a frame-independent relation among the parameters of the decay distribution of vector mesons into fermions. This relation is a generalization of the Lam-Tung identity, a result specific to Drell-Yan production in perturbative QCD, here shown to be equivalent to the dynamical condition that the dilepton always originates from a transversely polarized photon

A new approach to quarkonium polarization studies

Significant progress in understanding quarkonium production requires improved polarization measurements, fully considering the intrinsic multidimensionality of the problem. We propose a frame-invariant formalism which minimizes the dependence of the measured result on the experimental acceptance, facilitates the comparison with theoretical calculations, and provides a much needed control over systematic effects due to detector limitations and analysis biases. This formalism is a direct and generic consequence of the rotational invariance of the dilepton decay distribution and is independent of any assumptions specific to particular models of quarkonium production

The Relationship between Trigger Price and Punishment Period in Green and Porter (1984) Game made Endogenous

Green and Porter (1984) made a huge contribution to Industrial Organization Theory where a trigger price is defined by firms and whenever the price falls below this trigger price, the firms cease to produce at the monopoly level and enter into a punishment period. Our goal with this paper is to define, endogenously in the model, relationships between the trigger price and the punishment period, which were set exogenously in the original paper.Green and Porter (1984); trigger price; punishment period

Minimal physical constraints on the angular distributions of two-body boson decays

The angular distribution of the two-body decay of a boson of unknown properties is strongly constrained by angular momentum conservation and rotation invariance, as well as by the nature of the detected decay particles and of the colliding ones. Knowing the border between the "physical" and "unphysical" parameter domains defined by these "minimal constraints" (excluding specific hypotheses on what is still subject of measurement) is a useful ingredient in the experimental determinations of angular distributions and can provide model-independent criteria for spin characterizations. In particular, analysing the angular decay distribution with the general parametrization for the J = 2 case can provide a model-independent discrimination between the J = 0 and J = 2 hypotheses for a particle produced by two real gluons and decaying into two real photons

Rotation-invariant observables in parity-violating decays of vector particles to fermion pairs

The di-fermion angular distribution observed in decays of inclusively produced vector particles is characterized by two frame-independent observables, reflecting the average spin-alignment of the produced particle and the magnitude of parity violation in the decay. The existence of these observables derives from the rotational properties of angular momentum eigenstates and is a completely general result, valid for any J=1 state and independent of the production process. Rotation-invariant formulations of polarization and of the decay parity-asymmetry can provide more significant measurements than the commonly used frame-dependent definitions, also improving the quality of the comparisons between the measurements and the theoretical calculations.Comment: To be published in Phys. Rev.

Quarkonium production in the LHC era: a polarized perspective

Polarization measurements are usually considered as the most difficult challenge for the QCD description of quarkonium production. In fact, global data fits for the determination of the non-perturbative parameters of bound-state formation traditionally exclude polarization observables and use them as a posteriori verifications of the predictions, with perplexing results. With a change of perspective, we move polarization data to the centre of the study, advocating that they actually provide the strongest fundamental indications about the production mechanisms, even before we explicitly consider perturbative calculations. Considering psi(2S) and Y(3S) measurements from LHC experiments and state-of-the-art NLO short-distance calculations in the framework of non-relativistic QCD factorization (NRQCD), we perform a search for a kinematic domain where the polarizations can be correctly reproduced together with the cross sections, by systematically scanning the phase space and accurately treating the experimental uncertainties. This strategy provides a straightforward solution to the "quarkonium polarization puzzle" and reassuring signs that the theoretical framework is reliable. At the same time, the results expose unexpected hierarchies in the non-perturbative NRQCD parameters, that open new paths towards the understanding of bound-state formation in QCD.Comment: Submitted to Phys. Lett.

Quarkonium production at the LHC: a phenomenological analysis of surprisingly simple data patterns

The LHC quarkonium production measurements reveal a startling observation: the J/$\psi$, $\psi$(2S), $\chi_{c1,2}$ and $\Upsilon$(nS) $p_{\rm T}$-differential cross sections are compatible with one universal momentum scaling pattern. Considering also the absence of strong polarizations of directly and indirectly produced S-wave mesons, we are led to the conclusion that there is currently no evidence of a dependence of the partonic production mechanisms on the quantum numbers and mass of the final state. The experimental observations supporting this universal production scenario are remarkably significant, as shown by a new analysis approach, unbiased by specific theoretical calculations of partonic cross sections, which are only considered a posteriori, in comparisons with the data-driven results.Comment: Submitted to Phys. Lett.

From identical S- and P-wave pT/M spectra to maximally distinct polarizations: probing NRQCD with chi states

A global analysis of ATLAS and CMS measurements reveals that, at mid-rapidity, the directly-produced $\chi_{c1}$, $\chi_{c2}$ and J/$\psi$ mesons have differential cross sections of seemingly identical shapes, when presented as a function of the mass-rescaled transverse momentum, $p_{\rm T}/M$. This identity of kinematic behaviours among S- and P-wave quarkonia is certainly not a natural expectation of non-relativistic QCD (NRQCD), where each quarkonium state is supposed to reflect a specific family of elementary production processes, of significantly different $p_{\rm T}$-differential cross sections. Remarkably, accurate kinematic cancellations among the variegated NRQCD terms (colour singlets and octets) of its factorization expansion can lead to a surprisingly good description of the data. This peculiar tuning of the NRQCD mixtures leads to a clear prediction regarding the $\chi_{c1}$ and $\chi_{c2}$ polarizations, the only observables not yet measured: they should be almost maximally different from one another, and from the J/$\psi$ polarization, a striking exception in the global panorama of quarkonium production. Measurements of the difference between the $\chi_{c1}$, $\chi_{c2}$ and J/$\psi$ polarizations, complementing the observed identity of momentum dependences, represent a decisive probe of NRQCD.Comment: Submitted to European Physical Journal

Model-independent constraints on the shape parameters of dilepton angular distributions

The coefficients determining the dilepton decay angular distribution of vector particles obey certain positivity constraints and a rotation-invariant identity. These relations are a direct consequence of the covariance properties of angular momentum eigenstates and are independent of the production mechanism. The Lam-Tung relation can be derived as a particular case, simply recognizing that the Drell-Yan dilepton is always produced transversely polarized with respect to one or more quantization axes. The dilepton angular distribution continues to be characterized by a frame-independent identity also when the Lam-Tung relation is violated. Moreover, the violation can be easily characterized by measuring a one-dimensional distribution depending on one shape coefficient.Comment: 7 page

Octopus fishermen have a high rate of allergy sensitization to this species

Food allergy is an increasing worldwide problem. Food sensitization can occur by skin contact due to professional exposure and lead to clinical allergy, but data are sparse. In the Portuguese population diet, Octopus is usually fished and consumed. The major allergen (Oct v 1) in the muscle of the octopus Octopus vulgaris is tropomyosin, a highly conserved muscle protein with cross-reactivity between molluscs (bivalves, cephalopods, or gastropod) and also with arthropods (crustacea, insects and dust mites). The aim of this study was to investigate the prevalence of allergic sensitization to Octopus vulgaris on fishermen that captures it and establish its clinical relevance of it. It was applied a survey concerned to respiratory and food allergy. Skin prick tests with aeroallergens extracts and prick -to- prick skin tests with octopus were performed. The sample was 17 fishermen from a village that mainly capture of octopus, using pots and traps. Like in general population, 29% of fishermen have dust mite sensitization, but 35% of them has octopus sensitization, instead of the expected sensitization rate lower than 5%. Also, there was no significant correlation with dust mites sensitization (spearman rank order correlation p˂0,05). Our results show a higher prevalence rate, unrelated with dust mites sensitization, and probably due to professional exposure. This is the first study with octopus’ fishermen in Portugal. Larger studies with a molecular profile should be performed in order to establish the clinical relevance of this data and the healthcare impact of it.info:eu-repo/semantics/publishedVersio