1,946 research outputs found

    Universality-breaking effects in e+e−e^+e^- hadronic production processes

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    Recent BELLE measurements provide the cross section for single hadron production in e+e−e^+e^- annihilations, differential in thrust and in the hadron transverse momentum with respect to the thrust axis. Universality breaking effects due to process-dependent soft factors make it very difficult to relate this cross sections to those corresponding to hadron-pair production in e+e−e^+e^- annihilations, where transverse momentum dependent (TMD) factorization can be applied. The correspondence between these two cross sections is examined in the framework of the Collins-Soper-Sterman factorization, in the collinear as well as in the TMD approach. We propose a scheme that allows to relate the TMD parton densities defined in 1-hadron and in 2-hadron processes, neatly separating, within the soft and collinear parts, the non-perturbative terms from the contributions that can be calculated perturbatively. The regularization of rapidity divergences introduces cut-offs, the arbitrariness of which will be properly reabsorbed by means of a mechanism closely reminiscent of a gauge transformation. In this way, we restore the possibility to perform global phenomenological studies of TMD physics, simultaneously analyzing data belonging to different hadron classes.Comment: 60 pages, 15 figures, revised argument in section 6 - results unchanged, 1 figure added in section 3, references added, typos correcte

    Kinematic regions in the e+e− → hX factorized cross section in a 2-jet topology with thrust

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    Factorization theorems allow to separate out the universal, non-perturbative content of the hadronic cross section from its perturbative part, which can be computed in perturbative QCD, up to the desired order. In this paper, we derive a rigorous proof of factorization of the e+e−→h Xe^+ e^- \to h\,X cross section, sensitive to the transverse momentum of the detected hadron with respect to the thrust axis, in a completely general framework, based on the Collins-Soper-Sterman approach. The results are explicitly computed to NLO-NLL accuracy and subsequently generalized to all orders in perturbation theory. This procedure naturally leads to a partition of the e+e−→h Xe^+ e^- \to h\,X kinematics into three different regions, each associated to a different factorization theorem. In one of these regions, which covers the central and widest range, the factorization theorem has a new structure, which shares the features of both TMD and collinear factorization schemes. In the corresponding cross section, the role of the rapidity cut-off is investigated, as its physical meaning becomes increasingly evident. An algorithm to identify these three kinematic regions, based on ratios of observable quantities, is provided.Comment: 78 pages, 23 figure

    Is “Unconsummated Marriage” still an appropriate term? A snapshot of reality

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    The most shared definition of Unconsummated Marriage (UM) refers to “the failure to perform successful sexual intercourse at the beginning of the marriage. UM usually occurs in the first few nights of marriage and so it is frequently referred to as “honeymoon impotence” or “wedding night impotence”. In the Middle-Eastern (MES) and Western (WS) societies, sexuality follows different patterns in terms of meaning and rules. Moreover the evolution of societies all around the world created new contexts and kinds of relationship. This could hamper a correct taxonomy of such sexual dysfunction where a social variable seems crucial. Aim: To analyze and review data on UM all around the world, to understand if in different societies it refers to the same situation. Method: A review of published literature on UM from 1970 to date, was conducted. Results: Substantial difference emerged from MES to WS. In MES, sexuality is allowable only in marriage, while in WS sexuality and relationship are not strongly linked. This could suggest that the term “marriage” is unable to cover the phenomenon in such different countries. Moreover, the average time before the consultation, causal attribution and prevalence are very different in Western and Middle Eastern countries. Conclusion: We found that the term “first attempts dysfunction” could be better used to describe male, female or both difficulties related to ignorance about sexuality or state/performance anxiety. On the other hand over the individual category of sexual dysfunctions, we suggest a new term as “Unconsummated relationship”, where individual difficulties toward sexuality are involved creating a couple’s dysfunction. Keywords: Unconsummated marriage; Honeymoon impotence; White marriage; Vaginismus; Infertilit

    Acoustic neutrino detection in a Adriatic multidisciplinary observatory (ANDIAMO)

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    The existence of cosmic accelerators able to emit charged particles up to ZeV energies has been confirmed by the observations made in the last years by experiments such as Auger and Telescope Array. The interaction of such energetic cosmic-rays with gas or low energy photons, surrounding the astrophysical sources or present in the intergalactic medium, guarantee an ultra-high-energy neutrino related emission. When these energetic neutrinos interact in a medium produce a thermo-acoustic process where the energy of generated particle cascades can be conveyed in a pressure pulse propagating into the same medium. The kilometric attenuation length as well as the well-defined shape of the expected pulse suggest a large-area-undersea-array of acoustic sensors as an ideal observatory. For this scope, we propose to exploit the existing and no more operative offshore (oil rigs) powered platforms in the Adriatic sea as the main infrastructure to build an acoustic submarine array of dedicated hydrophones covering a surface area up to 10000 km2 and a volume up to 500 km3. In this work we describe the advantages of this detector concept using a ray tracing technique as well as the scientific goals linked to the challenging purpose of observing for the first time ultra-high-energy cosmic neutrinos. This observatory will be complementary to the dedicated radio array detectors with the advantages of avoiding any possible thermo-acoustic noise from the atmospheric muons

    Effect of Ru susbstitution on atomic displacements in the layered SmFe_{1-x}Ru_xAsO_{0.85}F_{0.15} superconductor

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    The effect of Ru substitution on the local structure of layered SmFe1−x_{1-x}Rux_xAsO0.85_{0.85}F0.15_{0.15} superconductor has been studied by As KK- and Sm L3L_3 - edges x-ray-absorption spectroscopy. The extended x-ray-absorption fine-structure measurements reveal distinct Fe-As and Ru-As bondlengths in the Ru substituted samples with the latter being ∌\sim0.03 \AA\ longer. Local disorder induced by the Ru substitution is mainly confined to the FeAs layer while the SmO spacer layer sustains a relative order, consistent with the x-ray-absorption near-edge structure spectra. The results suggest that, in addition to the order/disorder in the active active iron-arsenide layer, its coupling to the rare-earth\textminus oxygen spacer layer needs to be considered for describing the electronic properties of these layered superconductors

    Local structure of REFeAsO (RE=La, Pr, Nd, Sm) oxypnictides studied by Fe K-edge EXAFS

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    Local structure of REOFeAs (RE=La, Pr, Nd, Sm) system has been studied as a function of chemical pressure varied due to different rare-earth size. Fe K-edge extended X-ray absorption fine structure (EXAFS) measurements in the fluorescence mode has permitted to compare systematically the inter-atomic distances and their mean square relative displacements (MSRD). We find that the Fe-As bond length and the corresponding MSRD hardly show any change, suggesting the strongly covalent nature of this bond, while the Fe-Fe and Fe-RE bond lengths decrease with decreasing rare earth size. The results provide important information on the atomic correlations that could have direct implication on the superconductivity and magnetism of REOFeAs system, with the chemical pressure being a key ingredient

    Mafia and public spending: Evidence on the fiscal multiplier from a quasi-experiment

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    A law issued to combat political corruption and Mafia infiltration of city councils in Italy has resulted in episodes of large, unanticipated, temporary contractions in local public spending. Using these episodes as instruments, we estimate the output multiplier of spending cuts at provincial level—controlling for national monetary and fiscal policy, and holding the tax burden of local residents constant—to be 1.5. Assuming that lagged spending is exogenous to current output brings the estimate of the overall multiplier up to 1.9. These results suggest that local spending adjustment may be quite consequential for local activity. (JEL D72, E62, H71, K42) The work on this paper is part of PEGGED (Politics, Economics and Global Governance: The European Dimensions), Contract no. SSH7-CT-2008-217559 within the seventh Framework Programme for Research and Technological Development. Support from the Pierre Werner Chair Programme at the European University Institute is also gratefully acknowledged.This is the version of record, which can also be found on the publisher's website at: http://pubs.aeaweb.org/doi/pdfplus/10.1257/aer.104.7.2185 © American Economic Associatio

    A flexible quantum efficiency measurement device for photosensors testing

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    This paper presents a new quantum efficiency setup based on a 2D motorized stage, a wide spectrum xenon lamp, a beam splitter system, and two calibrated photodiodes for measuring the quantum efficiency (QE) of photosensors from PMTs (1 to 10 inches) to SIPM and photodiodes. The large area covered by the 2D stages permit to study the quantum efficiency of a matrix of multichannel photosensors in an automated way and PMTs with diameter up to ten inches. The setup offers high precision and accuracy in characterizing the quantum efficiency versus wavelength over the range of 250 nm to 1100 nm and in two dimensions with a positioning precision of ten microns. The setup monitors the light intensity synchronously with the output current yield from photosensors under test. This ensures the accuracy and repeatability of the measurements. The motorized stage allows precise positioning of the light source with respect to the active area. Moreover, the emission spectrum of the xenon lamp provides a broad range of illumination in terms of dynamics and wavelength span
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