Maurizio Bonesini - Academia.edu (original) (raw)

Papers by Maurizio Bonesini

The European Physical Journal C, 2000

A search for neutral Higgs bosons has been performed with the OPAL detector at LEP, using approxi... more A search for neutral Higgs bosons has been performed with the OPAL detector at LEP, using approximately 170 pb −1 of e + e − collision data collected at √ s ≈ 189 GeV. Searches have been performed for the Standard Model (SM) process e + e − →H 0 Z 0 and the MSSM processes e + e − →h 0 Z 0 , A 0 h 0. The searches are sensitive to the bb and τ + τ − decay modes of the Higgs bosons, and also to the MSSM decay mode h 0 →A 0 A 0. OPAL search results at lower centre-of-mass energies have been incorporated in the limits we set, which are valid at the 95% confidence level. For the SM Higgs boson, we obtain a lower mass bound of 91.0 GeV. In the MSSM, our limits are m h > 74.8 GeV and m A > 76.5 GeV, assuming tanβ>1, that the mixing of the scalar top quarks is either zero or maximal, and that the soft SUSY-breaking masses are 1 TeV. For the case of zero scalar top mixing, we exclude values of tan β between 0.72 and 2.19.

The European Physical Journal C

The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic es... more The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/c charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$$\pm 0.6$$ ± 0.6 % and 84.1$$\pm 0.6$$ ± 0.6 %, respectively. The efficie...

arXiv (Cornell University), Mar 15, 2023

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exp... more A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.

Journal of Instrumentation, 2020

tasks to be performed are partitioned in a hierarchical manner. 71, 130, 220, 224 warm interface ... more tasks to be performed are partitioned in a hierarchical manner. 71, 130, 220, 224 warm interface board (WIB) Digital electronics situated just outside the SP cryostat that receives digital data from the FEMBs over cold copper connections and sends it to the RCE FE readout hardware. 133, 160, 161 wavelength shifting (WLS) A material or process by which incident photons are absorbed by a material and photons are emitted at a different, typically longer, wavelength. 106

A generation of neutrino experiments have established that neutrinos mix and probably have mass. ... more A generation of neutrino experiments have established that neutrinos mix and probably have mass. The mixing phenomenon points to processes beyond those of the Standard Model, possibly at the Grand Unification energy scale. A extensive sequence of of experiments will be required to measure precisely all the parameters of the neutrino mixing matrix, culminating with the discovery and study of leptonic CP violation. As a first step, extensions of conventional pion/kaon decay beams, such as off-axis beams or low-energy super-beams, have been considered. These could yield first observations of ν µ → ν e transitions at the atmospheric frequency, which have not yet been observed, and a first measurement of θ 13. Experiments with much better flux control can be envisaged if the neutrinos are obtained from the decays of stored particles. One such possibility is the concept of beta beams provided by the decays of radioactive nuclei, that has been developed within the context of these studies. These would provide a pure (anti-)electron-neutrino beam of a few hundred MeV, and beautiful complementarity with a high-intensity, low-energy conventional beam, enabling experimental probes of T violation as well as CP violation. Ultimately, a definitive and complete set of measurements would offered by a Neutrino Factory based on a muon storage ring. This powerful machine offers the largest reach for CP violation, even for very small values of θ 13 .

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2002

Observation is made of rapidity-alignment o f K + K , and p p pairs which results from their asym... more Observation is made of rapidity-alignment o f K + K , and p p pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The K + K , and p p data are consistent with predictions from the fragmentation string model. However, the p p data strongly disagree with the conventional implementation of the cluster model. The non-perturbative process of`gluon splitting to diquarks' has to be incorporated into the cluster model for it to agree with the data. Local conservation of p T between particles nearby in rapidity i.e., p T compensation is analysed with respect to the thrust direction for +

Physics Letters B, 1995

Charmless hadronic decays of beauty mesons have been searched for using the data collected with t... more Charmless hadronic decays of beauty mesons have been searched for using the data collected with the DELPHI detector at the LEP collider. Several two, three and four-body decay modes have been investigated. Particle identication was used to distinguish the nal states with protons, kaons and pions. Three candidate events selected in two-body decay modes are interpreted as evidence for charmless B decays. No excess has been found in higher multiplicity modes and improved upper limits for some of the branching ratios are given.

Physics Letters B, 1996

A search for pair production of the lightest chargino at p s = 130.4 and 136.3 GeV has been carri... more A search for pair production of the lightest chargino at p s = 130.4 and 136.3 GeV has been carried out using the data sample corresponding to the 5.92 pb 1 recorded by the DELPHI detector during the high energy run of LEP in the last period of 1995. The theoretical reference model has been the Minimal Supersymmetric Standard Model with R-parity conservation. The three topologies expected for the decay of a pair of charginos, namely two acoplanar leptons plus missing energy (``), two jets and an isolated lepton plus missing energy (||`) and missing energy in a hadronic environment (4 |), were investigated. No evidence of a signal was found. Lower mass limits were derived for various scenarios, including the case of a low mass dierence between the chargino and the neutralino and of a light sneutrino. The mass limits range between 56.3 GeV/c 2 and the kinematic limit.

Physics Letters B, 1994

A total of about 900.000 Z 0 ! q q decays have been analyzed to measure the B 0 B 0 mixing probab... more A total of about 900.000 Z 0 ! q q decays have been analyzed to measure the B 0 B 0 mixing probability. T w o dierent b tagging techniques have been used: events with two leptons and events with one lepton and one. From a combination of the two methods the average mixing parameter, , w as determined to be (12:1 1:6(stat:) 0:4(syst:) 0:4(model))%.

Physics Letters B, 1995

A measurement of the A++ (1232) inclusive production in hadronic decays of the Z at LEP is presen... more A measurement of the A++ (1232) inclusive production in hadronic decays of the Z at LEP is presented, based on 1.3 million hadronic events collected by the DELPHI detector in the 1994 LEP running period. The DELPHI ring imaging Cherenkov counters are used for identifying hadrons. The average A ++(1232) multiplicity per hadronic event is 0.079 f 0.015 which is more than a factor of two below the JETSET, HERWIG and UCLA model predictions. It agrees with a recently proposed universal mass dependence of particle production rates in e+e-annihilations.

Physics Letters B, 1998

The data collected by DELPHI in 1996 have been used to measure the average charged particle multi... more The data collected by DELPHI in 1996 have been used to measure the average charged particle multiplicities and dispersions in q q events at centre-of-mass energies of p s = 161 GeV and p s = 172 GeV, and the average charge multiplicity i n W W e v ents at p s = 172 GeV. The multiplicities in q q events are

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

DELPHI (DEtector with Lepton, Photon and Hadron Identication) is a detector for e + e physics, de... more DELPHI (DEtector with Lepton, Photon and Hadron Identication) is a detector for e + e physics, designed to provide high granularity o v er a 4 solid angle, allowing an eective particle identication. It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.

Zeitschrift für Physik C Particles and Fields, 1995

Zeitschrift f�r Physik C Particles and Fields, 1993

From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are o... more From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are obtained and used for determining the contribution of the triple-gluon vertex. The relevant v ariables are the generalized Nachtmann Reiter angle NR and the opening angle of the two least energetic jets. A t to their two-dimensional distribution yields C A =C F = 2 : 12 0:35 and N C =N A = 0 : 46 0:19 where C A =C F is the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung from quarks, and N C =N A , the ratio of the number of quark colours to the number of gluons. This constitutes a convincing model-independent proof of the existence of the triple-gluon vertex, since its contribution is directly proportional to C A =C F. The results are in agreement with the values expected from QCD: C A =C F = 2:25, and N C =N A = 3 = 8.

The European Physical Journal C, 2011

The European Physical Journal C, 2000

A search for neutral Higgs bosons has been performed with the OPAL detector at LEP, using approxi... more A search for neutral Higgs bosons has been performed with the OPAL detector at LEP, using approximately 170 pb −1 of e + e − collision data collected at √ s ≈ 189 GeV. Searches have been performed for the Standard Model (SM) process e + e − →H 0 Z 0 and the MSSM processes e + e − →h 0 Z 0 , A 0 h 0. The searches are sensitive to the bb and τ + τ − decay modes of the Higgs bosons, and also to the MSSM decay mode h 0 →A 0 A 0. OPAL search results at lower centre-of-mass energies have been incorporated in the limits we set, which are valid at the 95% confidence level. For the SM Higgs boson, we obtain a lower mass bound of 91.0 GeV. In the MSSM, our limits are m h > 74.8 GeV and m A > 76.5 GeV, assuming tanβ>1, that the mixing of the scalar top quarks is either zero or maximal, and that the soft SUSY-breaking masses are 1 TeV. For the case of zero scalar top mixing, we exclude values of tan β between 0.72 and 2.19.

The European Physical Journal C

The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic es... more The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1 GeV/c charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1$$\pm 0.6$$ ± 0.6 % and 84.1$$\pm 0.6$$ ± 0.6 %, respectively. The efficie...

arXiv (Cornell University), Mar 15, 2023

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exp... more A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work.

Journal of Instrumentation, 2020

tasks to be performed are partitioned in a hierarchical manner. 71, 130, 220, 224 warm interface ... more tasks to be performed are partitioned in a hierarchical manner. 71, 130, 220, 224 warm interface board (WIB) Digital electronics situated just outside the SP cryostat that receives digital data from the FEMBs over cold copper connections and sends it to the RCE FE readout hardware. 133, 160, 161 wavelength shifting (WLS) A material or process by which incident photons are absorbed by a material and photons are emitted at a different, typically longer, wavelength. 106

A generation of neutrino experiments have established that neutrinos mix and probably have mass. ... more A generation of neutrino experiments have established that neutrinos mix and probably have mass. The mixing phenomenon points to processes beyond those of the Standard Model, possibly at the Grand Unification energy scale. A extensive sequence of of experiments will be required to measure precisely all the parameters of the neutrino mixing matrix, culminating with the discovery and study of leptonic CP violation. As a first step, extensions of conventional pion/kaon decay beams, such as off-axis beams or low-energy super-beams, have been considered. These could yield first observations of ν µ → ν e transitions at the atmospheric frequency, which have not yet been observed, and a first measurement of θ 13. Experiments with much better flux control can be envisaged if the neutrinos are obtained from the decays of stored particles. One such possibility is the concept of beta beams provided by the decays of radioactive nuclei, that has been developed within the context of these studies. These would provide a pure (anti-)electron-neutrino beam of a few hundred MeV, and beautiful complementarity with a high-intensity, low-energy conventional beam, enabling experimental probes of T violation as well as CP violation. Ultimately, a definitive and complete set of measurements would offered by a Neutrino Factory based on a muon storage ring. This powerful machine offers the largest reach for CP violation, even for very small values of θ 13 .

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 2002

Observation is made of rapidity-alignment o f K + K , and p p pairs which results from their asym... more Observation is made of rapidity-alignment o f K + K , and p p pairs which results from their asymmetric orientation in rapidity, with respect to the direction from primary quark to antiquark. The K + K , and p p data are consistent with predictions from the fragmentation string model. However, the p p data strongly disagree with the conventional implementation of the cluster model. The non-perturbative process of`gluon splitting to diquarks' has to be incorporated into the cluster model for it to agree with the data. Local conservation of p T between particles nearby in rapidity i.e., p T compensation is analysed with respect to the thrust direction for +

Physics Letters B, 1995

Charmless hadronic decays of beauty mesons have been searched for using the data collected with t... more Charmless hadronic decays of beauty mesons have been searched for using the data collected with the DELPHI detector at the LEP collider. Several two, three and four-body decay modes have been investigated. Particle identication was used to distinguish the nal states with protons, kaons and pions. Three candidate events selected in two-body decay modes are interpreted as evidence for charmless B decays. No excess has been found in higher multiplicity modes and improved upper limits for some of the branching ratios are given.

Physics Letters B, 1996

A search for pair production of the lightest chargino at p s = 130.4 and 136.3 GeV has been carri... more A search for pair production of the lightest chargino at p s = 130.4 and 136.3 GeV has been carried out using the data sample corresponding to the 5.92 pb 1 recorded by the DELPHI detector during the high energy run of LEP in the last period of 1995. The theoretical reference model has been the Minimal Supersymmetric Standard Model with R-parity conservation. The three topologies expected for the decay of a pair of charginos, namely two acoplanar leptons plus missing energy (``), two jets and an isolated lepton plus missing energy (||`) and missing energy in a hadronic environment (4 |), were investigated. No evidence of a signal was found. Lower mass limits were derived for various scenarios, including the case of a low mass dierence between the chargino and the neutralino and of a light sneutrino. The mass limits range between 56.3 GeV/c 2 and the kinematic limit.

Physics Letters B, 1994

A total of about 900.000 Z 0 ! q q decays have been analyzed to measure the B 0 B 0 mixing probab... more A total of about 900.000 Z 0 ! q q decays have been analyzed to measure the B 0 B 0 mixing probability. T w o dierent b tagging techniques have been used: events with two leptons and events with one lepton and one. From a combination of the two methods the average mixing parameter, , w as determined to be (12:1 1:6(stat:) 0:4(syst:) 0:4(model))%.

Physics Letters B, 1995

A measurement of the A++ (1232) inclusive production in hadronic decays of the Z at LEP is presen... more A measurement of the A++ (1232) inclusive production in hadronic decays of the Z at LEP is presented, based on 1.3 million hadronic events collected by the DELPHI detector in the 1994 LEP running period. The DELPHI ring imaging Cherenkov counters are used for identifying hadrons. The average A ++(1232) multiplicity per hadronic event is 0.079 f 0.015 which is more than a factor of two below the JETSET, HERWIG and UCLA model predictions. It agrees with a recently proposed universal mass dependence of particle production rates in e+e-annihilations.

Physics Letters B, 1998

The data collected by DELPHI in 1996 have been used to measure the average charged particle multi... more The data collected by DELPHI in 1996 have been used to measure the average charged particle multiplicities and dispersions in q q events at centre-of-mass energies of p s = 161 GeV and p s = 172 GeV, and the average charge multiplicity i n W W e v ents at p s = 172 GeV. The multiplicities in q q events are

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1996

DELPHI (DEtector with Lepton, Photon and Hadron Identication) is a detector for e + e physics, de... more DELPHI (DEtector with Lepton, Photon and Hadron Identication) is a detector for e + e physics, designed to provide high granularity o v er a 4 solid angle, allowing an eective particle identication. It has been operating at the LEP (Large Electron-Positron) collider at CERN since 1989. This article reviews its performance.

Zeitschrift für Physik C Particles and Fields, 1995

Zeitschrift f�r Physik C Particles and Fields, 1993

From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are o... more From the combined data of 1990 and 1991 of the DELPHI experiment at LEP, 13057 4-jet events are obtained and used for determining the contribution of the triple-gluon vertex. The relevant v ariables are the generalized Nachtmann Reiter angle NR and the opening angle of the two least energetic jets. A t to their two-dimensional distribution yields C A =C F = 2 : 12 0:35 and N C =N A = 0 : 46 0:19 where C A =C F is the ratio of the coupling strength of the triple-gluon vertex to that of gluon bremsstrahlung from quarks, and N C =N A , the ratio of the number of quark colours to the number of gluons. This constitutes a convincing model-independent proof of the existence of the triple-gluon vertex, since its contribution is directly proportional to C A =C F. The results are in agreement with the values expected from QCD: C A =C F = 2:25, and N C =N A = 3 = 8.

The European Physical Journal C, 2011

Nuclear Inst. and Methods in Physics Research, A 936, 2019

The idea of the CHNET-TANDEM experiment is to develop and optimize a non-destructive technique, w... more The idea of the CHNET-TANDEM experiment is to develop and optimize a non-destructive technique, which allows analysis deep inside the sample with a good spatial resolution, using a negative muon beam. By selecting the primary muon energies appropriately, bulk analysis can be performed without destructing the sample. The experimental setup used for this experiment, made by 2 hodoscopes and 5 HpGe, allowed us to collect very interesting preliminary data concerning scan momentum, positioning and centering of the samples by means of two hodoscopes, analysis of standard material targets and elemental characterization of Nuragic ''Bronze Age'' votive ship fragments. Contents