Individual events at high-energy colliders like the LHC can be represented by a sequence of measurements, or ‘point patterns’. Starting from this generic data representation, we build a simple Bayesian probabilistic model for event measurements useful for unsupervised event classification in beyond the standard model (BSM) studies. In order to arrive to this model we assume that the event measurements are exchangeable (and apply De Finetti’s representation theorem), the data is discrete, and measurements are generated frommultiple ‘latent’ distributions (called themes). The resulting probabilistic model for collider events is a mixed-membership model known as Latent Dirichlet Allocation (LDA), a model extensively used in natural language processing applications. By training on mixed dijet samples of QCD and BSM, we demonstrate that a two-theme LDA model can learn to distinguish in (unlabelled) jet substructure data the hidden new physics patterns produced by a non-trivial BSM signature from a much larger QCD background.
{"title":"Uncovering hidden new physics patterns in collider events using Bayesian probabilistic models","authors":"D. Faroughy","doi":"10.22323/1.390.0238","DOIUrl":"https://doi.org/10.22323/1.390.0238","url":null,"abstract":"Individual events at high-energy colliders like the LHC can be represented by a sequence of measurements, or ‘point patterns’. Starting from this generic data representation, we build a simple Bayesian probabilistic model for event measurements useful for unsupervised event classification in beyond the standard model (BSM) studies. In order to arrive to this model we assume that the event measurements are exchangeable (and apply De Finetti’s representation theorem), the data is discrete, and measurements are generated frommultiple ‘latent’ distributions (called themes). The resulting probabilistic model for collider events is a mixed-membership model known as Latent Dirichlet Allocation (LDA), a model extensively used in natural language processing applications. By training on mixed dijet samples of QCD and BSM, we demonstrate that a two-theme LDA model can learn to distinguish in (unlabelled) jet substructure data the hidden new physics patterns produced by a non-trivial BSM signature from a much larger QCD background.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82727282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Camerlingo, M. Alviggi, V. Canale, M. Pietra, C. Donato, P. Iengo, M. Iodice, F. Petrucci, G. Sekhniaidze
Micromegas are among the most promising micro pattern gaseous detector (MPGD) technologies for applications in high energy physics (HEP). Micromegas are very versatile. They can be used for precision tracking and trigger, in particle flow sampling calorimetry, as anode planes for RICH detectors or for time projection chambers. Driven mainly by future upgrades of existing experiments at high-luminosity LHC (HL-LHC) and for applications at future accelerators, we started an R&D project to push further this technology for operations under very high particle flow up to rates of tens MHz/cm, three orders of magnitude higher than current applications. The miniaturization of the readout elements and the optimization of the spark protection system, as well as the stability and robustness under operation, are the primary challenges of the project.
{"title":"Rate capability and stability studies on small-Pad resistive Micromegas","authors":"M. Camerlingo, M. Alviggi, V. Canale, M. Pietra, C. Donato, P. Iengo, M. Iodice, F. Petrucci, G. Sekhniaidze","doi":"10.22323/1.390.0825","DOIUrl":"https://doi.org/10.22323/1.390.0825","url":null,"abstract":"Micromegas are among the most promising micro pattern gaseous detector (MPGD) technologies for applications in high energy physics (HEP). Micromegas are very versatile. They can be used for precision tracking and trigger, in particle flow sampling calorimetry, as anode planes for RICH detectors or for time projection chambers. Driven mainly by future upgrades of existing experiments at high-luminosity LHC (HL-LHC) and for applications at future accelerators, we started an R&D project to push further this technology for operations under very high particle flow up to rates of tens MHz/cm, three orders of magnitude higher than current applications. The miniaturization of the readout elements and the optimization of the spark protection system, as well as the stability and robustness under operation, are the primary challenges of the project.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87724286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Klitzner, O. Biebel, J. Bortfeldt, B. Flierl, M. Herrmann, R. Hertenberger
Floating strip Micromegas detectors are high-rate capable particle detectors with excellent spatial and time resolution, allowing single particle tracking with fluxes up to at least 7 MHz/cm2. The amplified ionization charge is collected on copper anode strips kept at a slightly floating electrical potential. The charge signal is coupled to two layers of perpendicular readout strips in x and y, insulated by thin Kapton layers. A complete understanding of the signal formation in the detector, particularly on the orthogonal y-strips, is achieved: simulations disentangle the signal coupling due to alternating weighting field lines with respect to the ion velocity vector and the response of charge sensitive front-end electronics. Different two-dimensional anode designs with optimized strip geometry have been developed based on the simulations. We present the performance of the detector for the different designs measured in 20 MeV proton/neutron and 180 GeV pion/muon beams, using APV25 front-end electronics.
{"title":"A Novel Two-Dimensional Readout Design for Floating Strip Micromegas Detectors","authors":"F. Klitzner, O. Biebel, J. Bortfeldt, B. Flierl, M. Herrmann, R. Hertenberger","doi":"10.22323/1.390.0853","DOIUrl":"https://doi.org/10.22323/1.390.0853","url":null,"abstract":"Floating strip Micromegas detectors are high-rate capable particle detectors with excellent spatial and time resolution, allowing single particle tracking with fluxes up to at least 7 MHz/cm2. The amplified ionization charge is collected on copper anode strips kept at a slightly floating electrical potential. The charge signal is coupled to two layers of perpendicular readout strips in x and y, insulated by thin Kapton layers. A complete understanding of the signal formation in the detector, particularly on the orthogonal y-strips, is achieved: simulations disentangle the signal coupling due to alternating weighting field lines with respect to the ion velocity vector and the response of charge sensitive front-end electronics. Different two-dimensional anode designs with optimized strip geometry have been developed based on the simulations. We present the performance of the detector for the different designs measured in 20 MeV proton/neutron and 180 GeV pion/muon beams, using APV25 front-end electronics.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"184 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80525336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Search for scalar top quark pair production in the top corridor region with CMS","authors":"A. T. Fernandez","doi":"10.22323/1.390.0311","DOIUrl":"https://doi.org/10.22323/1.390.0311","url":null,"abstract":"","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"46 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82219071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Non-zero neutrino masses are experimentally established since the Nobel-Prize winning discovery of neutrino oscillation. This opens the possibility to distinguish the Majorana and Dirac nature of neutrinos and in turn, allows to search for lepton number violation in the neutrino sector. A lepton number violation through Majorana neutrinos is a prime candidate for creating the baryon number asymmetry and could explain why there is more matter than anti-matter in the Universe. The absolute neutrino mass scale is strongly constrained but still unknown today. Precision β-decay experiments, cosmological probes and, neutrinoless double beta decay determine the neutrino mass scale with different observables. This proceedings summarizes the current status of the international experimental efforts aiming to measure the absolute neutrino mass scale and to search for lepton number violation in the neutrino sector.
{"title":"Lepton Number Violation and Neutrino Masses","authors":"B. Lehnert","doi":"10.22323/1.390.0027","DOIUrl":"https://doi.org/10.22323/1.390.0027","url":null,"abstract":"Non-zero neutrino masses are experimentally established since the Nobel-Prize winning discovery of neutrino oscillation. This opens the possibility to distinguish the Majorana and Dirac nature of neutrinos and in turn, allows to search for lepton number violation in the neutrino sector. A lepton number violation through Majorana neutrinos is a prime candidate for creating the baryon number asymmetry and could explain why there is more matter than anti-matter in the Universe. The absolute neutrino mass scale is strongly constrained but still unknown today. Precision β-decay experiments, cosmological probes and, neutrinoless double beta decay determine the neutrino mass scale with different observables. This proceedings summarizes the current status of the international experimental efforts aiming to measure the absolute neutrino mass scale and to search for lepton number violation in the neutrino sector.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"57 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85115325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Search for new phenomena using jets at CMS","authors":"D. Karasavvas","doi":"10.22323/1.390.0255","DOIUrl":"https://doi.org/10.22323/1.390.0255","url":null,"abstract":"","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"30 6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90577249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Signatures of complex new physics in charged current $B$ anomalies","authors":"Suman Kumbhakar","doi":"10.22323/1.390.0389","DOIUrl":"https://doi.org/10.22323/1.390.0389","url":null,"abstract":"","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91017092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hyper-Kamiokande, scheduled to begin construction as soon as 2020, is a next generation underground water Cherenkov detector, based on the highly successful Super-Kamiokande experiment. It will serve as a far detector, 295 km away, of a long baseline neutrino experiment for the upgraded J-PARC beam in Japan. It will also be a detector capable of observing— far beyond the sensitivity of the Super-Kamiokande detector — proton decay, atmospheric neutrinos, and neutrinos from astronomical sources. An Outer Detector (OD) consisting of PMTs mounted behind the inner detector PMTs and facing outwards to view the outer shell of the cylindrical tank, would provide topological information to identify interactions originating from particles outside the inner detector. Any optimization would lead to a significant improvement for the physics goals of the experiment, which are the measurement of the CP leptonic phase and the determination of the neutrino mass hierarchy. An innovative new setup using small 3" PMTs is being proposed for the Hyper-Kamiokande OD. They would give better redundancy, spatial, and angular resolution, as there would be twice or three times more photosensors that the original 8" design proposal of the experiment, and for a reduced cost. Several 3" PMT candidates considered for the Hyper-Kamiokande OD have been characterized for this study. They all show a very low dark counts and good collection efficiency, which makes them excellent choice to be used in the experiment.
{"title":"The Outer Detector (OD) system for Hyper-Kamiokande experiment","authors":"S. Zsoldos","doi":"10.22323/1.390.0886","DOIUrl":"https://doi.org/10.22323/1.390.0886","url":null,"abstract":"Hyper-Kamiokande, scheduled to begin construction as soon as 2020, is a next generation underground water Cherenkov detector, based on the highly successful Super-Kamiokande experiment. It will serve as a far detector, 295 km away, of a long baseline neutrino experiment for the upgraded J-PARC beam in Japan. It will also be a detector capable of observing— far beyond the sensitivity of the Super-Kamiokande detector — proton decay, atmospheric neutrinos, and neutrinos from astronomical sources. An Outer Detector (OD) consisting of PMTs mounted behind the inner detector PMTs and facing outwards to view the outer shell of the cylindrical tank, would provide topological information to identify interactions originating from particles outside the inner detector. Any optimization would lead to a significant improvement for the physics goals of the experiment, which are the measurement of the CP leptonic phase and the determination of the neutrino mass hierarchy. An innovative new setup using small 3\" PMTs is being proposed for the Hyper-Kamiokande OD. They would give better redundancy, spatial, and angular resolution, as there would be twice or three times more photosensors that the original 8\" design proposal of the experiment, and for a reduced cost. Several 3\" PMT candidates considered for the Hyper-Kamiokande OD have been characterized for this study. They all show a very low dark counts and good collection efficiency, which makes them excellent choice to be used in the experiment.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81874528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thanks to the low background, negligible pileup and generally clean environement at 4? colliders, a rich program of physics beyond the Standard Model (BSM) can be explored with precision measurements, complementing searches at LHC and future ?? colliders. We review some recent studies aimed at evaluating the reach and sensitivity of the next generation 4? colliders, the LHeC and FCC-eh, in probing a few BSMmodels, in particular compressed scenarios of supersymmetry, long-lived particles and dark sector, charged Higgs and leptoquarks.
{"title":"Beyond Standard Model Physics at the LHeC and the FCC-eh","authors":"G. Azuelos, M. D'Onofrio, O. Fischer, LHeC","doi":"10.22323/1.390.0227","DOIUrl":"https://doi.org/10.22323/1.390.0227","url":null,"abstract":"Thanks to the low background, negligible pileup and generally clean environement at 4? colliders, a rich program of physics beyond the Standard Model (BSM) can be explored with precision measurements, complementing searches at LHC and future ?? colliders. We review some recent studies aimed at evaluating the reach and sensitivity of the next generation 4? colliders, the LHeC and FCC-eh, in probing a few BSMmodels, in particular compressed scenarios of supersymmetry, long-lived particles and dark sector, charged Higgs and leptoquarks.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"112 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73367608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many new physics models, e.g., compositeness, extra dimensions, extended Higgs sectors, supersymmetric theories, and dark sector extensions, are expected to manifest themselves in the final states with leptons. Searches in CMS for new phenomena in the final states that include leptons, focusing on the recent results obtained using the Run-II data set collected at the LHC are described here.
{"title":"Search for new phenomena in leptonic final states at CMS","authors":"Saranya Ghosh","doi":"10.22323/1.390.0246","DOIUrl":"https://doi.org/10.22323/1.390.0246","url":null,"abstract":"Many new physics models, e.g., compositeness, extra dimensions, extended Higgs sectors, supersymmetric theories, and dark sector extensions, are expected to manifest themselves in the final states with leptons. Searches in CMS for new phenomena in the final states that include leptons, focusing on the recent results obtained using the Run-II data set collected at the LHC are described here.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":"40 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83024502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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