Search results for "High Energy Physics::Phenomenology"
showing 10 items of 5791 documents
Measurement of top quark and W boson polarisation observables with t-channel single-top-quark events in the ATLAS experiment
2017
El trabajo de la tesis se enmarca dentro del programa de física de la Colaboración ATLAS para el análisis de los datos producidos por el Gran Colisionador de Hadrones (LHC) situado en el CERN. La primera parte del trabajo desarrollado se centra en los estudios realizados para mejorar los algoritmos y el procedimiento seguido para el alineamiento del detector de trazas de ATLAS. El conocimiento de la posición exacta que ocupan los elementos que componen el detector de trazas determina la resolución con la que la trayectoria de una partícula puede ser reconstruida. La posición de dichos elementos se ve afectada por cambios en las condiciones de trabajo, como el apagado y encendido del sistema…
Orbital angular momentum parton distributions in quark models
1999
At the low energy, {\sl hadronic}, scale we calculate Orbital Angular Momentum (OAM) twist-two parton distributions for the relativistic MIT bag model and for non-relativistic quark models. We reach the scale of the data by leading order evolution in perturbative QCD. We confirm that the contribution of quarks and gluons OAM to the nucleon spin grows with $Q^2$, and it can be relevant at the experimental scale, even if it is negligible at the hadronic scale, irrespective of the model used. The sign and shape of the quark OAM distribution at high $Q^2$ may depend strongly on the relative size of the OAM and spin distributions at the hadronic scale. Sizeable quark OAM distributions at the had…
"Table 1" of "Charm-quark fragmentation fractions and production cross section at midrapidity in pp collisions at the LHC"
2022
Ratio of prompt open-charm hadrons H$_\mathrm{c}$ and inclusive $\mathrm{J}/\psi$ mesons over D$^0$-meson production cross section in pp collisions at $\sqrt{s} = 5.02$ TeV.
Quasiconformal Jordan Domains
2020
We extend the classical Carath\'eodory extension theorem to quasiconformal Jordan domains $( Y, d_{Y} )$. We say that a metric space $( Y, d_{Y} )$ is a quasiconformal Jordan domain if the completion $\overline{Y}$ of $( Y, d_{Y} )$ has finite Hausdorff $2$-measure, the boundary $\partial Y = \overline{Y} \setminus Y$ is homeomorphic to $\mathbb{S}^{1}$, and there exists a homeomorphism $\phi \colon \mathbb{D} \rightarrow ( Y, d_{Y} )$ that is quasiconformal in the geometric sense. We show that $\phi$ has a continuous, monotone, and surjective extension $\Phi \colon \overline{ \mathbb{D} } \rightarrow \overline{ Y }$. This result is best possible in this generality. In addition, we find a n…
Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at √s = 7 TeV
2017
Two-particle angular correlations were measured in pp collisions at s√=7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon–baryon and anti-baryon–anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an op…
Proton shape fluctuation and its relation to DIS
2018
We review the recent progress in extracting the proton fluctuating substructure by studying exclusive processes at HERA, and the applications of these developments in the interpretation of the LHC heavy ion data. The possibilities to extract the proton geometry directly from the LHC high-multiplicity proton-nucleus and proton-proton collision data is also discussed. peerReviewed
Measurement of D-meson production at mid-rapidity in pp collisions at √s = 7 TeV
2017
The production cross sections for prompt charmed mesons D0, D+, D∗+ and D+s were measured at mid-rapidity in proton–proton collisions at a centre-of-mass energy s√=7 TeV with the ALICE detector at the Large Hadron Collider (LHC). D mesons were reconstructed from their decays D0→K−π+, D+→K−π+π+, D∗+→D0π+, D+s→ϕπ+→K−K+π+, and their charge conjugates.With respect to previous measurements in the same rapidity region, the coverage in transverse momentum (pT) is extended and the uncertainties are reduced by a factor of about two. The accuracy on the estimated total cc¯¯ production cross section is likewise improved. The measured pT-differential cross sections are compared with the results of thre…
Approach to equilibrium of a quarkonium in a quark-gluon plasma
2018
We derive equations of motion for the reduced density matrix of a heavy quarkonium in contact with a quark-gluon plasma in thermal equilibrium. These equations allow in particular a proper treatment of the regime when the temperature of the plasma is comparable to the binding energy of the quarkonium. These equations are used to study how the quarkonium approaches equilibrium with the plasma, and we discuss the corresponding entropy increase, or free energy decrease, depending on the temperature regime. The effect of collisions can be accounted for by the generalization of the imaginary potential introduced in previous studies, and from which collision rates are derived. An important outcom…
Effective Field Theories for heavy probes in a hot QCD plasma and in the early universe
2017
There are many interesting problems in heavy-ion collisions and in cosmology that involve the interaction of a heavy particle with a medium. An example is the dissociation of heavy quarkonium seen in heavy-ion collisions. This was believed to be due to the screening of chromoelectric fields that prevents the heavy quarks from binding, however in the last years several perturbative and lattice computations have pointed out to the possibility that dissociation is due to the finite lifetime of a quarkonium state inside the medium. Regarding cosmology, the study of the behavior of heavy Majorana neutrinos in a hot medium is important to understand if this model can explain the origin of dark ma…
Mixing of pseudoscalar-baryon and vector-baryon in meson-baryon interaction and the generation of resonances
2014
215 páginas. Tesis Doctoral del Departamento de Física Teórica de la Universidad de Valencia y del Instituto de Física Corpuscular (IFIC).