6,589 research outputs found
Tracking at LHC
Precise tracking is an indispensable tool for the study of many phenomena at new energy frontier accessible with the CERN Large Hadron Collider (LHC). The tracking detectors of ATLAS and CMS have been designed to cope with the harsh experimental conditions of the LHC interaction region. In this paper, we discuss and compare the tracking performance of these two detectors
Pre-packaged food products business to consumer (B2C) distance selling and information obligations in Italian mass market retailers
The supply and sale of food online are on the rise. The value of e-commerce in Europe has been estimated in 602 billion euros in 2017, 324 million people in the old continent purchase online. In the European area, the Netherlands and Italy are the countries where the e-commerce market grew faster in the last five years. Nevertheless, in Italy the spread of online shopping has reached the 89.9% of the population between 11 and 74 years old. The access to the Internet, as declared by 43 million Italians, it is carried out from fixed or mobile locations. In terms of revenues the food sector recorded a +24% among the different sectors facing one of the higher grows in terms of percentages. The regulatory framework that disciplines the food products distance selling can be traced back to two fundamental pillars: the European legislation on e-commerce on the one side and the food information to consumers on the other side. Under article 14 of the Regulation (EU) No. 1169/2011, the European legislator states that the mandatory information, as indicated in article 9, shall be available to the consumer before the purchase is concluded and when the product is delivered. The study aims at verifying: the level of compliance by Italians MMR with the information regulation about food products distance selling in relation to (a) the fulfillment of the obligation concerning mandatory provisions and (b) the fulfillment of the obligations concerning availability and readability of the information provided. The research has been conducted analyzing the websites of the ten largest Italian MMR and in particular: if the mandatory information were provided, the availability of the information according to the Regulation (EU) 1169/2011; the number of clicks needed to identify the food product in the website and the number of clicks Non required to obtain all the information. The observation testified a substantial compliance with the information obligations according to the European regulation. Differently, when considering the availability and readability of the information, from the analysis emerged that consumers have to follow a path that is not immediate and intuitive. Conclusions are provided in relation to the presented research
Exact Results on e+ e- --> e+ e- + 2 Photons at SLC/LEP Energies
We use the spinor methods of the CALKUL collaboration, as realized by Xu,
Zhang and Chang, to calculate the differential cross section for e+ e- --> e+
e- + 2 photons for c.m.s. energies in the SLC/LEP regime. An explicit complete
formula for the respective cross section is obtained. The leading log
approximation is used to check the formula. Applications of the formula to high
precision luminosity calculations at SLC/LEP are discussed.Comment: 16 pages(LaTeX), UTHEP-92-0601 (contains corrected figures
Gaseous Dark Matter Detectors
Dark Matter detectors with directional sensitivity have the potential of
yielding an unambiguous positive observation of WIMPs as well as discriminating
between galactic Dark Matter halo models. In this article, we introduce the
motivation for directional detectors, discuss the experimental techniques that
make directional detection possible, and review the status of the experimental
effort in this field.Comment: 19 pages, review on gaseous directional dark matter detectors
submitted to New Journal of Physic
Tracing CP violation in the production of top quark pairs by multiple TeV proton-proton collisions
We investigate the possibilities of searching for non-standard CP violation
in at multiple TeV collision energies. A general kinematic
analysis of the underlying partonic production processes and
in terms of their density matrices is given. We evaluate
the CP-violating parts of these matrices in two-Higgs doublet extensions of the
standard model (SM) and give results for CP asymmetries at the parton level. We
show that these asymmetries can be traced by measuring suitable observables
constructed from energies and momenta of the decay products of and . We find CP-violating effects to be of the order of and show that
possible contaminations induced by SM interactions are savely below the
expected signals.Comment: 24 pages, SLAC-PUB-6403, PITHA 93/43, 9 Figs. available upon request.
Written in LaTe
Incorporation of QCD Effects in Basic Corrections of the Electroweak Theory
We study the incorporation of QCD effects in the basic electroweak
corrections \drcar, \drcarw, and \dr. They include perturbative
\Ord{\alpha\alpha_s} contributions and threshold effects. The latter
are studied in the resonance and Green-function approaches, in the framework of
dispersion relations that automatically satisfy relevant Ward identities.
Refinements in the treatment of the electroweak corrections, in both the \ms\
and the on-shell schemes of renormalization, are introduced, including the
decoupling of the top quark in certain amplitudes, its effect on
\hat{e}^2(\mz) and \sincarmz, the incorporation of recent results on the
leading irreducible \Ord{\alpha^2} corrections, and simple expressions for the
residual, i.e.\ ``non-electromagnetic'', parts of \drcar, \drcarw, and \dr. The
results are used to obtain accurate values for \mw\ and \sincarmz, as functions
of \mt\ and \mh. The higher-order effects induce shifts in these parameters
comparable to the expected experimental accuracy, and they increase the
prediction for \mt\ derived from current measurements. The \ms\ and the
on-shell calculations of \dr, in a recently proposed formulation, are compared
and found to be in excellent agreement over the wide ranges 60\GeV \leq \mh
\leq 1 \TeV, \mz \leq \mt \leq 250 \GeV.Comment: 51 pages (needs doublespace, equations, and cite styles
A New Model for Fermion Masses in Supersymmetric Grand Unified Theories
We present a simple model for fermion mass matrices and quark mixing in the
context of supersymmetric grand unified theories and show its agreement with
experiment. Our model realizes the GUT mass relations , , in a new way and is easily consistent with values of
suggested by MSSM fits to LEP data.Comment: Latex, 8 p., ITP-SB-93-37 (revised version contains minor changes in
some wording and citations; no changes in analytic or numerical results.
Chargino Production at LEP2 in a Supergravity Model
In the framework of a particular supergravity model which provides a natural
solution to the --problem we show how the discovery of a chargino at LEP2
and the measurement of its mass and production cross--section, together with
the measurement of the mass of the lightest neutralino, would determine the
entire Higgs and SUSY spectrum. We give detailed predictions for the Higgs and
SUSY spectrum as a function of the chargino production cross--section, for
constant values of the lightest chargino and gluino masses.Comment: 11 pages, latex, 4 figures uufile
R_b and New Physics: A Comprehensive Analysis
We survey the implications for new physics of the discrepancy between the LEP
measurement of and its Standard Model prediction. Two broad classes of
models are considered: () those in which new Z\bbar b couplings arise at
tree level, through or -quark mixing with new particles, and ()
those in which new scalars and fermions alter the Z \bbar b vertex at one
loop. We keep our analysis as general as possible in order to systematically
determine what kinds of features can produce corrections to of the right
sign and magnitude. We are able to identify several successful mechanisms,
which include most of those which have been recently been proposed in the
literature, as well as some earlier proposals (\eg\ supersymmetric models). By
seeing how such models appear as special cases of our general treatment we are
able to shed light on the reason for, and the robustness of, their ability to
explain .Comment: 60 pages, 8 figures, plain tex, uses epsf. Final version to appear in
Phys. Rev. D; propgating sign error corrected in eqs. 78, 87, 88, 89, 98, and
107; results unchange
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