605 research outputs found
Absolute determination of D_s branching ratios and f_{D_s} extraction at a neutrino factory
A method for a direct measurement of the exclusive D_s branching ratios and
of the decay constant f_{D_s} with a systematical error better than 5% is
presented. The approach is based on the peculiar vertex topology of the
anti-neutrino induced diffractive charm events. The statistical accuracy
achievable with a neutrino factory is estimated
Heavy quark studies with nuclear emulsions
Emulsions have started particle physics with the discovery of natural
radioactivity by Becquerel in 1896. The development of the ``nuclear
emulsions'' made it possible to detect tracks of single particle and to perform
detailed measurements of their interactions. The discovery of the pion in 1947
was the first, spectacular demonstration of their unique features for the
direct observation of the production and decay of short-lived particles, with
negligible or very low background. In particular, these features are now
exploited for studies of heavy quark physics in experiments where nuclear
emulsions are combined with electronic detectors and profit is taken of the
remarkable technological progress in automated analysis. In these experiments,
neutrinos provide a selective probe for specific quark flavors. Interesting
results on charm production and decay are expected in the very near future.Comment: To be published on the book for the eightieth birthday of Roberto
Salmeron, World Scientifi
Prediction of charm-production fractions in neutrino interactions
The way a charm-quark fragments into a charmed hadron is a challenging
problem both for the theoretical and the experimental particle physics.
Moreover, in neutrino induced charm-production, peculiar processes occur such
as quasi-elastic and diffractive charm-production which make the results from
other experiments not directly comparable. We present here a method to extract
the charmed fractions in neutrino induced events by using results from
, , experiments while taking into account the
peculiarities of charm-production in neutrino interactions. As results, we
predict the fragmentation functions as a function of the neutrino energy and
the semi-muonic branching ratio, , and compare them with the available
data
Virtual prototyping of medieval weapons for historical reconstruction of siege scenarios starting from topography and archaeological investigations
Chronicles of sieges to castles or fortresses, using âmachinaeâ, can often be found in historical sources. Moreover, archaeological excavations of castles or fortresses has brought to light rocks or projectiles whose carving suggests a military usage. Nevertheless, chronicles and discoveries alone, are seldom enough to propose a faithful reconstruction of these machines. Therefore, the aim of this research is the development of methodologies for reconstructing virtual scenarios of sieges, starting from the scarce information available. In order to achieve it, a procedure for the virtual reconstruction of the siege machine has been set up, focusing on typology and dimensions of the machines, also investigating possible fire positions according to topography. The entire procedure has been developed using the siege of Cervara di Romaâs Rocca as a case study. Late medieval chronicles (end of 13th Century) report the siege brought by the papal army in order to restore the jurisdiction on the Cervaraâs stronghold, following the insurrection of a group of vassals headed by a monk named Pelagio. The discovery, in the area of the Rocca, of a stone that could have been used as a projectile confirms what reported. The proposed methodology is composed of two parts. The first one is connected to the study of the âinternal ballisticsâ, to understand the performances and to build virtual models of siege machines. The second part is the study of the âexternal ballisticsâ, then to the positioning and shooting ability of possible machines, analysing the topography of the area. In this paper, we present the feasibility of this methodology through the preliminary results achieved correlating internal and external ballistics
Study of defect formation in Al 7050 alloys
The Al 7050 alloy is an Al-Zn-Mg-Cu-Zr alloy having good mechanical properties. This alloy has been developed in order to overcome stress corrosion cracking problems that characterise 7xxx Al alloys. Despite Al 7050 is widely used for aerospace applications, it can be subjected to crack initiation and propagation during the manufacturing process. In this work cracked Al 7050 components have been analysed in order to identify possible causes of crack formation such as coarse intermetallic phase presence, voids or wrong mechanical machining processes
A search for Z' in muon neutrino associated charm production
In many extensions of the Standard Model the presence of an extra neutral
boson, Z', is invoked. A precision study of weak neutral-current exchange
processes involving only second generation fermions is still missing. We
propose a search for Z' in muon neutrino associated charm production. This
process only involves Z' couplings with fermions from the second generation. An
experimental method is thoroughly described using an ideal detector. As an
application, the accuracy reachable with present and future experiments has
been estimated.Comment: 13 pages, 3 figures, late
SBV regularity for Hamilton-Jacobi equations in
In this paper we study the regularity of viscosity solutions to the following
Hamilton-Jacobi equations In particular, under the
assumption that the Hamiltonian is uniformly convex, we
prove that and belong to the class .Comment: 15 page
Directionality preservation of nuclear recoils in an emulsion detector for directional dark matter search
Nuclear emulsion is a well-known detector type proposed also for the
directional detection of dark matter. In this paper, we study one of the most
important properties of direction-sensitive detectors: the preservation by
nuclear recoils of the direction of impinging dark matter particles. For
nuclear emulsion detectors, it is the first detailed study where a realistic
nuclear recoil energy distribution with all possible recoil atom types is
exploited. Moreover, for the first time we study the granularity effect on the
emulsion detector directional performance. As well as we compare nuclear
emulsion with other directional detectors: in terms of direction preservation
nuclear emulsion outperforms the other detectors for WIMP masses above 100
GeV/c.Comment: Prepared for submission to JCA
- âŠ