SearcharxivSearch

arXiv subjects

Francesco Spanò

Publications and source records attributed to Francesco Spanò.

8 recordsLinked to original sources

Physics to the rescue?

A vast body of literature addresses the complex nature of science's reproducibility crisis. In contrast with this perceived complexity, some recent papers from the discipline of physics suggests that irreproducibility does not point to a systemic crisis, but is, on the contrary, a sign that the science system works properly. These works, while acknowledging the difference between physics and other disciplines mired in the reproducibility crisis, hint that all disciplines could learn from Physics. The present work suggests that this optimistic message, when addressed to struggling disciplines, may invite complacency over other relevant dimensions of crisis, delay its solution, and get into the way of a truly joint effort from all disciplines to tackle the important social and environmental predicaments of the present age.

physics.soc-ph

Unfolding with Gaussian Processes

A method to perform unfolding with Gaussian processes (GPs) is presented. Using Bayesian regression, we define an estimator for the underlying truth distribution as the mode of the posterior. We show that in the case where the bin contents are distributed approximately according to a Gaussian, this estimator is equivalent to the mean function of a GP conditioned on the maximum likelihood estimator. Regularisation is introduced via the kernel function of the GP, which has a natural interpretation as the covariance of the underlying distribution. This novel approach allows for the regularisation to be informed by prior knowledge of the underlying distribution, and for it to be varied along the spectrum. In addition, the full statistical covariance matrix for the estimator is obtained as part of the result. The method is applied to two examples: a double-peaked bimodal distribution and a falling spectrum.

physics.data-an

Discovering and profiling Z' bosons using asymmetry observables in top quark pair production with the lepton-plus-jets final state at the LHC

The sensitivity of top quark pair production at the Large Hadron Collider to the presence and nature of an underlying Z' boson is studied, accounting for six-fermion decay with full tree-level Standard Model ttbar interference and all intermediate particles allowed off-shell. Focus is placed on the lepton-plus-jets final state, emulating experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in jet-top assignment. Considering a resonance with mass of 4 TeV, and assuming 300 inverse fb of proton-proton collisions with a centre of mass energy of 13 TeV data, a combination of forward-backward and top polarisation asymmetries are shown to distinguish Z' embedded by different classes of Grand-Unified-Theory-inspired models. In combination with the differential cross section, they may be used to increase the significance of the signal when tested against the Standard Model, as shown using a likelihood-based statistical test.

hep-ph

Discriminating Z' signals in semileptonic top pair production at the LHC

We investigate the sensitivity of top pair production to the properties of different Beyond the Standard Model theories embedding a new neutral boson. We include six-fermion decay, and account for the full tree-level Standard Model ttbar interference, with all intermediate particles allowed off-shell. We focus on those observables best suited to the lepton-plus-jets final state at the LHC, and simulate the resulting experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in quark-top assignment. In particular, we demonstrate the use of asymmetry observables to probe the coupling structure of a new neutral resonance, in addition to cases in which these asymmetries may even form complementary discovery observables in combination with the differential cross section.

hep-ph

Using asymmetry observables to discover and distinguish Z' signals in top pair production with the lepton-plus-jets final state at the LHC

We study the sensitivity of top pair production with six-fermion decay at the LHC to the presence and nature of an underlying Z' boson, accounting for full tree-level Standard Model ttbar interference, with all intermediate particles allowed off-shell. We concentrate on the lepton-plus-jets final state and simulate experimental conditions, including kinematic requirements and top quark pair reconstruction in the presence of missing transverse energy and combinatorial ambiguity in jet-top assignment. We focus on the differential mass spectra of the cross section and asymmetry observables, especially demonstrating the use of the latter in probing the coupling structure of a new neutral resonance, in addition to cases in which the asymmetry forms a complementary discovery observable.

hep-ph

Studies of top quark production with the ATLAS detector at the LHC

A review is presented of the most recent measurements of top quark strong and electroweak production performed by using data collected with the ATLAS detector in proton-proton collisions at sqrt(s) = 7 and 8 TeV at the Large Hadron Collider corresponding to integrated luminosities of up to about 4.7/fb and 20/fb, respectively.

hep-ex

Top Quark Production at the LHC

Top quark production in proton proton collisions at the Large Hadron Collider (LHC) is reviewed using data collected by the ATLAS and CMS detectors. Most recent results on searches for new physics related to top quark production mechanism are included.

hep-ex

Top Physics at ATLAS and CMS

The potential for top quark physics of the ATLAS and CMS experiments at the Large Hadron Collider is surveyed ranging from top quark "re-discovery" and its use as a calibration tool to initial and later stage measurements.

hep-ex