Search results for " PDF"
showing 10 items of 17 documents
Observation of $Z$ production in proton-lead collisions at LHCb
2014
The first observation of $Z$ boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of $\sqrt{s_{NN}}=5~\text{TeV}$ is presented. The data sample corresponds to an integrated luminosity of $1.6~\text{nb}^{-1}$ collected with the LHCb detector. The $Z$ candidates are reconstructed from pairs of oppositely charged muons with pseudorapidities between 2.0 and 4.5 and transverse momenta above $20~\text{GeV}/c$. The invariant dimuon mass is restricted to the range $60-120~\text{GeV}/c^2$. The $Z$ production cross-section is measured to be \begin{eqnarray*} ��_{Z\to��^+��^-}(\text{fwd})&=&13.5^{+5.4}_{-4.0}\text{(stat.)}\pm1.2\text{(syst.)}~\text{nb} …
Sistemi informativi 3D per i BB.CC. e l'archeologia: il Castello di Maredolce a Palermo
2014
Il mondo della ricerca nel campo dei BB.CC. sta guardando con sempre maggior interesse all’uso di tecnologie informatiche integrate, che consentano di fornire e condividere in rete dati quantitativi e qualitativi, geometrici, posizionali, alfanumerici, relativi ai BB.CC., sfruttando l’interazione tra banche dati e modelli 3D. Tali modelli, dunque, oltre a fornire una ricostruzione virtuale del monumento con la possibilità di navigare ed analizzare l’oggetto in dettaglio, costituiscono lo strumento per accedere ad informazioni eterogenee (testi, immagini, sequenze video, ecc.) sui manufatti, raccolte ed organizzate in database relazionali interrogabili, al fine di una piena comprensione e co…
Platelet-derived growth factor alpha mediates the proliferation of peripheral T-cell lymphoma cells via an autocrine regulatory pathway.
2014
Peripheral T-cell lymphomas not otherwise specified (PTCL/NOS) are very aggressive tumors characterized by consistent aberrant expression of platelet-derived growth factor receptor alpha (PDGFRA). In this study, we aimed to identify the determinants of PDGFRA activity in PTCL/NOS and to elucidate the biological consequences of its activation. We observed overexpression of the PDGFRA gene by gene expression profiling in most of the tested PTCLs and confirmed the expression of PDGFRA and phospho-PDGFRA using immunohistochemistry. The integrity of the PDFGRA locus was demonstrated using several different approaches, including massive parallel sequencing and Sanger sequencing. PDGF-AA was found…
The EPPS16 nuclear PDFs
2017
We report on EPPS16 - the first analysis of NLO nuclear PDFs where LHC p-Pb data (Z, W, dijets) have been directly used as a constraint. In comparison to our previous fit EPS09, also data from neutrino-nucleus deeply-inelastic scattering and pion-nucleus Drell-Yan process are now included. Much of the theory framework has also been updated from EPS09, including a consistent treatment of heavy quarks in deeply-inelastic scattering. However, the most notable change is that we no longer assume flavour-blind nuclear modifications for valence and sea quarks. This significantly reduces the theoretical bias. All the analysed data are well reproduced and the analysis thereby supports the validity o…
Can we fit nuclear PDFs with the high-x CLAS data?
2020
AbstractNuclear parton distribution functions (nuclear PDFs) are non-perturbative objects that encode the partonic behaviour of bound nucleons. To avoid potential higher-twist contributions, the data probing the high-x end of nuclear PDFs are sometimes left out from the global extractions despite their potential to constrain the fit parameters. In the present work we focus on the kinematic corner covered by the new high-x data measured by the CLAS/JLab collaboration. By using the Hessian re-weighting technique, we are able to quantitatively test the compatibility of these data with globally analyzed nuclear PDFs and explore the expected impact on the valence-quark distributions at high x. W…
An update on nuclear PDFs at the LHeC
2017
The prospects for a measurement of nuclear parton distribution functions (PDFs) at the Large Hadron--Electron Collider are discussed in the light of recent progress made in the front of global analysis of nuclear PDFs.
Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons
2015
Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise.
Response spectrum analysis of frame structures: reliability-based comparison between complete quadratic combination and damping-adjusted combination
2019
In the framework of seismic design of structures, response spectrum analysis (RSA) is the most commonly used approach in practice. The most popular combination rule is the complete quadratic combination (CQC) which is also prescribed by the most of seismic design codes and is based on the assumptions that the seismic acceleration is a white noise process and the peak factor ratios associated to the total and modal responses are unitary. Recently, the damping adjusted combination (DAC) rule has been developed for base-isolated structures to overcome the aforementioned simplified assumptions. Although it has been proved that the simplifications about peak factors lead to noticeable errors in …
Measurement of azimuthal hadron asymmetries in semi-inclusive deep inelastic scattering off unpolarised nucleons
2014
Spin-averaged asymmetries in the azimuthal distributions of positive and negative hadrons produced in deep inelastic scattering were measured using the CERN SPS muon beam at $160$ GeV/c and a $^6$LiD target. The amplitudes of the three azimuthal modulations $\cos\phi_h$, $\cos2\phi_h$ and $\sin\phi_h$ were obtained binning the data separately in each of the relevant kinematic variables $x$, $z$ or $p_T^{\,h}$ and binning in a three-dimensional grid of these three variables. The amplitudes of the $\cos \phi_h$ and $\cos 2\phi_h$ modulations show strong kinematic dependencies both for positive and negative hadrons.
Pion–nucleus Drell–Yan data as a novel constraint for nuclear PDFs
2017
We have studied the prospects of using the Drell-Yan dilepton process in pion-nucleus collisions as a novel input in the global analysis of nuclear parton distribution functions (nPDFs). In a NLO QCD framework, we find the measured nuclear cross-section ratios from the NA3, NA10 and E615 experiments to be largely insensitive to the pion parton distributions and also compatible with the EPS09 and nCTEQ15 nPDFs. These data sets can thus be, and in EPPS16 have been, included in global nPDF analyses without introducing significant new theoretical uncertainties or tension with the other data. In particular, we explore the constraining power of these data sets on the possible flavour asymmetry in…