2,055 research outputs found
Erratum to: “Weak corrections to gluon-induced top–antitop hadro-production” [Phys. Lett. B 639 (2006) 513]
No full textAbstractThis is an Erratum to a Letter of ours [S. Moretti, M.R. Nolten, D.A. Ross, Phys. Lett. B 639 (2006) 513]. After its publication, we have discovered a mistake in a numerical program that affects the results presented therein. We provide here the corrected version
Weak corrections to gluon-induced top-antitop hadro-production
No full textWe calculate purely weak virtual one-loop corrections to the production cross section of top–antitop pairs at the Large Hadron Collider via the gluon–gluon fusion subprocess. We find very small negative corrections to the total cross section, of order ?0.6%, but significantly larger effects to the differential one, particularly in the transverse momentum distribution, of order ?5% to ?10% (in observable regions). In case of parity-conserving spin-asymmetries of the final state, corrections are typically of a few negative percent, with the exception of positive and negative peaks at +12% and ?5%, respectively (near where the tree-level predictions change sign), while those arising in parity-violating asymmetries (which are identically zero in QCD) are typically at a level of a few permille
Weak effects in proton beam asymmetries at polarised RHIC and beyond
No full textWe report on a calculation of the full one-loop weak corrections through the order to parton–parton scattering in all possible channels at the Relativistic Heavy Ion Collider (RHIC) running with polarised pp beams (RHIC-Spin). This study extends the analysis previously carried out for the case of 2?2 subprocesses with two external gluons, by including all possible four-quark modes with and without an external gluon. The additional contributions due to the new four-quarks processes are extremely large, of order 50 to 100% (of either sign), not only in the case of parity-violating beam asymmetries but also for the parity-conserving ones and (although to a more limited extent) the total cross section. Such effects on the CP-violating observables would be an astounding 5 times larger for the case of the LHC with polarised beams—which has been discussed as one of the possible upgrades of the CERN machine—whereas they would be much reduced for the case of the CP-conserving ones as well as the cross section
Weak corrections to four-parton processes
No full textWe report on a calculation of the ‘mixed’ strong and (purely) weak corrections through the order αS2αW to parton–parton processes in all possible channels at hadron colliders entering the single jet inclusive cross section. At both Tevatron and LHC, such effects are always negligible (below permille level) in the total integrated cross section whilst they become sizable in differential rates. Specifically, if such corrections are defined with respect to the full leading-order result of [equ'n], we find that, at the FNAL accelerator, they can reach the -5% benchmark in the jet transverse energy (at the kinematical limit of the machine, rendering their detection quite difficult). At the CERN collider, in the same observable, they exceed the -10% level already at 1 TeV and can reach -40% at 4 TeV, kinematic regions where such corrections will be comfortably observable for standard luminosity. In addition, such corrections are somewhat sensitive to the factorisation/renormalisation scale choice
Weak corrections and high Et jets at the Fermilab Tevatron
No full textWe calculate one-loop (purely) weak (W) corrections of [script O](alphaS2alphaW) to the partonic cross section of two jets at Tevatron and prove that they can be larger than the tree-level [script O](alphaSalphaEW) and [script O](alphaEW2) electroweak (EW) ones. At high transverse energy of the jets, all such corrections may lead to detectable effects of, e.g., -10% or so, with respect to the leading-order (LO) QCD term of [script O](alphaS2), for the highest value so far probed by Run 2, depending on the factorization/renormalization scale. Besides, they increase significantly with jet transverse energy. Hence, our results show that EW corrections may be needed to fit the standard model (SM) to present and future Tevatron jet data.<br/
Electroweak radiative corrections to hadronic precision observables at TeV energies
No full textWe illustrate the impact of full one-loop weak corrections onto b-jet-, prompt-photon- and Z-production at Tevatron and Large Hadron Collider (LHC) <br/
One-loop weak corrections to the bb̄ cross section at TeV energy hadron colliders
No full textWe investigate one-loop weak corrections to the production cross section of two b-jets at Tevatron and Large Hadron Collider (LHC). We establish that they are small at inclusive level but dominant in exclusive observables that have a non-trivial dependence on the helicity structure of the hard subprocesses. Such effects can serve as a test of the Standard Model (SM) and, conversely, they should be taken into account in future experimental analyses aiming at extracting possible signals of new physics
Esperienza ed evento della verità. Pratica filosofica e astrazione scientifica nel pensiero di A.N. Whitehead
No full textThis article analyzes the relationship between philosophy, experience and event in A.N. Whitehead’s thought. From the critics of the concept of object, the author retraces and describes the peculiar “abstract-concrete dialectic”, at the center of the researches concerning the perceptual experience.
Furthermore, according to Whitehead’s later works, she demonstrates how the philosophical practice is different from all other kinds of science, although it requires science itself because of the co-implication of object and event, abstraction and recognition
Il "Guerrin Meschino" di Gesualdo Bufalino : un'"opra" in versi
No full textGesualdo Bufalino first published Il Guerrin Meschino in 1991 in a non-commercial edition. In 1993, after a deep revision, he re-published his work with publisher Bompiani: the novel has a modified plot, and the author decided to insert three new poems in addition to the opening and closing poems, formerly present in 1991’s edition. This paper, in its entirety supported by handwritten material preserved at Fondazione Gesualdo Bufalino (Comiso), is divided in two parts: the first part illustrates the differences between the first and the second edition, the second part provides a critical edition of the five poems
A FEW WORDS ABOUT THE TEACHER. IN MEMORY OF THE EXCELLENT TEACHER AND SCIENTIST M.R. SAPIN
No full textM.R. Sapin (1925–2015) was a professor at I.M. Sechenov First Moscow State Medical University, honorary academician of Russian academy of medical sciences (1988), and an outstanding representative of the Moscow anatomical school of the middle of XX – early XXI century. From the very beginning of his medical training, Mikhail Romanovich got interested in anatomy, especially in angiology and lymphology, and later concentrated on its studying. The author of more than 30 text books and guidelines for schools, universities, and colleges, Mikhail Romanovich was the doctoral and thesis advisor of 51 Ph.D. and approximately 70 MD dissertations. M.R. Sapin made a significant contribution to the development of anatomical education providing the departments with a various range of dry and wet specimens. His stunning and effective work as a tutor was highly appreciated by his students and colleagues, Russian and foreign anatomists. M.R. Sapin was the leader of the Laboratory of Functional Anatomy since 1972, president of the International Association of Morphologists (1992–2006), chairman of the expert commission of Higher Attestation Commission (1959–1994), etc. A man of a great willpower, M.R. Sapin faced a lot of obstacles in his life and research work but overcame that all successfully. The article presents the most important facts of anatomist’s career and lifetime.</jats:p
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