arXiv subjects

Michael Joseph Morello

Publications and source records attributed to Michael Joseph Morello.

8 recordsLinked to original sources

arXiv2026

A real-time demonstrator of track reconstruction with FPGAs at LHCb

The upgraded LHCb detector has started its Run 3 of data taking in 2022, with a completely overhauled DAQ system, reading out and processing the full detector data at every LHC bunch crossing (30 MHz average rate). At the same time, an intense R&D activity is taking place, with the aim of further improving the real-time data processing performance of LHCb, in view of "Upgrade II", where luminosity will be increased. In this work, we describe the experience gained with a prototype device for a 30 MHz real-time tracking in the LHCb VELO detector, implemented in state-of-art PCIe-hosted FPGA cards interconnected by fast optical links. The system has been processing live LHCb data opportunistically during physics data taking, thanks to a dedicated TestBed facility fed by the experiment monitoring system. We describe, amongst other things, the system used to organise and optimise the high-speed distribution of data to the components, and the synchronisation with the most updated alignment constants to be used in track reconstruction.

physics.ins-det↗

arXiv2024

LHC beam monitoring via real-time hit reconstruction in the LHCb VELO pixel detector

The increasing computing power and bandwidth of programmable digital devices opens new possibilities in the field of real-time processing of HEP data. The LHCb collaboration is exploiting these technology advancements in various ways to enhance its capability for complex data reconstruction in real time. Amongst them is the real-time reconstruction of hits in the VELO pixel detector, by means of real-time cluster-finding embedded in the readout board firmware. This reconstruction, in addition to saving data-acquisition bandwidth and high-level trigger computing resources, also enables further useful applications in precision monitoring and diagnostics of LHC beam conditions. In fact, clusters of pixels, being more reliable and robust indications of physical particle hits than raw pixel counts, are also exempt from the complications associated to the reconstruction of tracks, that involves alignment issues and is sensitive to multi-layer efficiency products. In this paper, we describe the design and implementation of a flexible system embedded in the readout firmware of the VELO detector, allowing real-time measurement of cluster density in several parts of the detector simultaneously, and separately for every bunch ID, for every single LHC collision, without any slowdown of data acquisition. Quantitative applications of this system to luminosity measurement and beam monitoring are demonstrated.

hep-ex↗

arXiv2022

Mixing and $CP$ violation in $D^0 \to K^- π^+$ decays

We review the experimental methods to measure mixing and time-dependent $C\!P$ violation in $D^0$ decays into two hadrons. While these phenomena are usually neglected for $D^0 \to K^- π^+$ decays, this approximation is not always justified. In particular, it produces a bias on the measurement of the parameter $y_{CP}$, when this is performed by relying on $D^0 \to K^- π^+$ decays as a normalisation channel, whose size is around 40% of the precision of the current world average. Finally, we estimate the sensitivity to the weak mixing phases achievable by studying $D^0 \to K^- π^+$ and untagged $D \to K^- π^+$ decays, where $D$ stands for either of the $D^0$ and $\bar{D}^0$ mesons. Contrary to Cabibbo-suppressed $D^0 \to h^+ h^-$ decays, these decay channels allow to measure these phases without final-state dependent nuisance contributions from the decay amplitudes, but their sensitivity is lower by a factor of six.

hep-ph↗

arXiv2013

TeVatron Direct CP Violation Results

I report some recent results on direct CP violation measurements in hadronic decays collected by the upgraded Collider Detector (CDF II) at the Fermilab Tevatron: CP-violating asymmetries in the two-body non-leptonic charmless decays of $b$-hadrons, the first reconstruction in hadron collisions of the suppressed decays $B^- \to D(\to K^+π^-)K^-$ and $B^- \to D(\to K^+π^-)π^-$, and the measurement of TP asymmetries in the $B^{0}_{s} \to ϕϕ$ decays.

hep-ex↗

arXiv2012

Measurement of CP Violation in $D^0/\bar{D}^0$

Charm physics has played all along a central role in particle physics, however the level of attention on it has tremendously increased in the last years because of the observation of "fast" $D^0-\bar{D}^0$ flavour oscillations and because of very recent observed hints of CP violation. While in the past these would have been unambiguously interpreted as signs of New Physics, the revisitation of theoretical expectations, prompted by the latest experimental measurements, makes the picture not clear. This brief review covers the current status of CP-violating measurements in the $D^0-\bar{D}^0$ system, both on the experimental and theoretical side.

hep-ex↗

arXiv2011

B Physics at the TeVatron

The CDF and DØ experiments at the Tevatron $p\bar{p}$ collider established that extensive and detailed exploration of the $b$--quark dynamics is possible in hadron collisions, with results competitive and supplementary to those from $e^+e^-$ colliders. This provides a rich, and highly rewarding program that is currently reaching full maturity. I report a few recent world-leading results on rare decays, CP-violation in $B^0_s$ mixing, $b\to s$ penguin decays, and charm physics.

hep-ex↗

arXiv2010

CP violation in the D0 -> pi+ pi- decay at CDF

We report a measurement of the \CP\ violating asymmetry in $D^0\toπ^+π^-$ decays using approximately 215,000 decays reconstructed in about $5.94$ fb$^{-1}$ of CDF data. We use the strong $D^{\star +}\to D^0π^+$ decay ("$D^{\star}$ tag") to identify the flavor of the charmed meson at production time and exploit \CP-conserving strong $c\bar{c}$ pair-production in $p\bar{p}$ collisions. Higher statistic samples of Cabibbo-favored $D^0\to K^-π^+$ decays with and without $D^{\star}$ tag are used to highly suppress systematic uncertainties due to detector effects. The result, $\Acp(D^0 \to π^{+}π^{-}) = \bigl[0.22\pm0.24\stat\pm0.11\syst\bigr]%$, is the world's most precise measurement to date and it is fully consistent with no \CP\ violation.

hep-ex↗

arXiv2010

Flavor Changing Neutral Current at the Tevatron

Processes involving flavor changing neutral currents (FCNC) provide excellent signatures with which to search for evidence of new physics. They have very small branching fractions in the Standard Model since they are highly suppressed by Glashow-Iliopoulos-Maiani (GIM) mechanism. They occur only through higher order diagrams, and new particles contributions can provide a significant enhancements, which would be an uniquevocal signs of physics beyond the Standard Model. In this paper we present the most recent measurements on FCNC processes performed by CDF and D0 Collaborations, while last section is devote to the charm physics at CDF.

hep-ex↗