We discuss a 1+2 dimensional model with unconventional supersymmetry at the boundary of an AdS 4 , N -extended supergravity. The resulting features of the supersymmetric boundary open the possibility of describing the electronic properties of graphene-like 2D materials at the Dirac points K and K’ , exploiting a top-down approach. The Semenoff and Haldane-type masses entering the corresponding Dirac equations can be then extrapolated from the geometric parameters of the model describing the substrate.
{"title":"Supersymmetric theories and graphene","authors":"A. Gallerati","doi":"10.22323/1.390.0662","DOIUrl":"https://doi.org/10.22323/1.390.0662","url":null,"abstract":"We discuss a 1+2 dimensional model with unconventional supersymmetry at the boundary of an AdS 4 , N -extended supergravity. The resulting features of the supersymmetric boundary open the possibility of describing the electronic properties of graphene-like 2D materials at the Dirac points K and K’ , exploiting a top-down approach. The Semenoff and Haldane-type masses entering the corresponding Dirac equations can be then extrapolated from the geometric parameters of the model describing the substrate.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89270327","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}
Yu-Chen Chen, Chengjian Lin, Yen-Jie Lee, P. Chang
The enhancement of charged-particle pairs with large pseudorapidity difference and small azimuthal angle difference, often referred to as the “ridge signal”, is a phenomenon widely observed in high multiplicity proton-proton, proton-ion and deutron-ion collisions, which is not yet fully understood. In heavy-ion collisions, the hydrodynamic expansion of the Quark-Gluon Plasma is the most popular explanation of the ridge signal. Measurements in the 4+4− collision system, without the complexities introduced by hadron structure in the initial state, can be a new opportunity to examine the formation of a ridge signal. The first measurement of two-particle angular correlation functions in high multiplicity 4+4− collisions at √ B = 10.52 GeV is reported. About 31.5 fb−1 hadronic 4+4− annihilation data collected by the Belle detector at KEKB are used in this study. Two-particle angular correlation functions are measured over the full azimuth and large pseudorapidity intervals which are defined by either the electron beam axis or the event thrust as a function of charged particle multiplicity. The measurement in the event thrust analysis, with mostly quark and anti-quark pairs determining the reference axis, is sensitive to soft gluon emissions associated with the outgoing (anti-)quarks. No significant ridge signal is observed with analyses performed in either coordinate system. Near-side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various 4+4− event generators and expected to provide new constraints to the phenomenological models in the low collision energy regime.
{"title":"Search for long range flow-like correlation in hadronic $e^{+}e^{-}$ collisions with Belle","authors":"Yu-Chen Chen, Chengjian Lin, Yen-Jie Lee, P. Chang","doi":"10.22323/1.390.0541","DOIUrl":"https://doi.org/10.22323/1.390.0541","url":null,"abstract":"The enhancement of charged-particle pairs with large pseudorapidity difference and small azimuthal angle difference, often referred to as the “ridge signal”, is a phenomenon widely observed in high multiplicity proton-proton, proton-ion and deutron-ion collisions, which is not yet fully understood. In heavy-ion collisions, the hydrodynamic expansion of the Quark-Gluon Plasma is the most popular explanation of the ridge signal. Measurements in the 4+4− collision system, without the complexities introduced by hadron structure in the initial state, can be a new opportunity to examine the formation of a ridge signal. The first measurement of two-particle angular correlation functions in high multiplicity 4+4− collisions at √ B = 10.52 GeV is reported. About 31.5 fb−1 hadronic 4+4− annihilation data collected by the Belle detector at KEKB are used in this study. Two-particle angular correlation functions are measured over the full azimuth and large pseudorapidity intervals which are defined by either the electron beam axis or the event thrust as a function of charged particle multiplicity. The measurement in the event thrust analysis, with mostly quark and anti-quark pairs determining the reference axis, is sensitive to soft gluon emissions associated with the outgoing (anti-)quarks. No significant ridge signal is observed with analyses performed in either coordinate system. Near-side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various 4+4− event generators and expected to provide new constraints to the phenomenological models in the low collision energy regime.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81156232","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}
The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino oscillation experiment with a 53 km distance from reactors and a 700 m overburden, currently under construction in South China. The primary goal is to measure the neutrino mass ordering with better than 3 σ after 6 years of data taking. Therefore 20 kton high transparency liquid scintillator, high coverage (75%) of photomultiplier tubes and low backgrounds are needed to achieve an energy resolution of 3% at 1MeV and a calibration accuracy better than 1%. This is the most challenging design in the present reactor neutrino experiments throughout the world. Such a large detector also has a huge potential to measure with sub-percent accuracy three neutrino oscillation parameters and detect neutrinos from various terrestrial and extra-terrestrial sources. This talk will present the status and progress of the JUNO detector and of Taishan Antineutrino Observatory (JUNO-TAO), a satellite experiment of JUNO, designed to measure the reactor antineutrino spectrum with sub-percent energy resolution and provide a reference spectrum for future reactor neutrino experiments.
{"title":"Status and progress of the JUNO detector","authors":"Jilei Xu","doi":"10.22323/1.390.0882","DOIUrl":"https://doi.org/10.22323/1.390.0882","url":null,"abstract":"The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino oscillation experiment with a 53 km distance from reactors and a 700 m overburden, currently under construction in South China. The primary goal is to measure the neutrino mass ordering with better than 3 σ after 6 years of data taking. Therefore 20 kton high transparency liquid scintillator, high coverage (75%) of photomultiplier tubes and low backgrounds are needed to achieve an energy resolution of 3% at 1MeV and a calibration accuracy better than 1%. This is the most challenging design in the present reactor neutrino experiments throughout the world. Such a large detector also has a huge potential to measure with sub-percent accuracy three neutrino oscillation parameters and detect neutrinos from various terrestrial and extra-terrestrial sources. This talk will present the status and progress of the JUNO detector and of Taishan Antineutrino Observatory (JUNO-TAO), a satellite experiment of JUNO, designed to measure the reactor antineutrino spectrum with sub-percent energy resolution and provide a reference spectrum for future reactor neutrino experiments.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81987202","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}
S. Qian, Lishuang Ma, Hao Guo, Guorui Huang, Q. Hu, Li Zhen, Shulin Liu, Z. Ning, S. Peng, Ren Ling, Detan Su, Su Jianning, Si Shuguang, Qi Wu, Wang Xingchao, Wang Ning, Wu Kai, Zhigang Wang, Zhile Wang, M. Yan, Yao Zhu, Lingfeng Zhang, Yinhong Zhang
Based on the development of the 20-inch large-area MCP-PMT, the research of a small, ultra-fast MCP-PMT is carried out with the cooperation of Institute of High Energy Physics (IHEP), Chinese Academy of Sciences and Northern Night Vision Technology Co., LTD (NNVT). The structural simulation and optimization of the fast-time PMT was first performed by a Monte Carlo-based approach. Accurate measurements of the time performance of greatest interest are then tested and validated. IHEP and NNVT have successfully developed single-anode, 4 times 4-anode and 8 times 8-anode sample tubes suitable for different application scenarios. While maintaining the single-photon detection capability of the sample tube, the limiting time resolution of the
{"title":"The status of the R&D of Ultra Fast 8 times 8 Readout MCP-PMTs in IHEP","authors":"S. Qian, Lishuang Ma, Hao Guo, Guorui Huang, Q. Hu, Li Zhen, Shulin Liu, Z. Ning, S. Peng, Ren Ling, Detan Su, Su Jianning, Si Shuguang, Qi Wu, Wang Xingchao, Wang Ning, Wu Kai, Zhigang Wang, Zhile Wang, M. Yan, Yao Zhu, Lingfeng Zhang, Yinhong Zhang","doi":"10.22323/1.390.0867","DOIUrl":"https://doi.org/10.22323/1.390.0867","url":null,"abstract":"Based on the development of the 20-inch large-area MCP-PMT, the research of a small, ultra-fast MCP-PMT is carried out with the cooperation of Institute of High Energy Physics (IHEP), Chinese Academy of Sciences and Northern Night Vision Technology Co., LTD (NNVT). The structural simulation and optimization of the fast-time PMT was first performed by a Monte Carlo-based approach. Accurate measurements of the time performance of greatest interest are then tested and validated. IHEP and NNVT have successfully developed single-anode, 4 times 4-anode and 8 times 8-anode sample tubes suitable for different application scenarios. While maintaining the single-photon detection capability of the sample tube, the limiting time resolution of the","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88257551","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}
The upgrade of the ALICE Inner Tracking System (ITS) aims at improving the capabilities of ALICE in terms of read-out rate as well as track pointing resolution and track finding efficiency, especially for particles with low transverse momenta. The new ITS will be a low material budget detector with high granularity and read-out speed. It comprises seven concentric layers of Monolithic Active Pixel Sensors (MAPS) with a total active surface of about 10 m2. The developed MAPS are based on the TowerJazz 180 nm CMOS technology. The sensor is called ALPIDE. In this paper we present the setup used for measurements with inclined tracks and we discuss the sensor efficiency obtained using π beams with a momentum of 6 GeV/c at the Proton Synchrotron (PS) at CERN. Some sensors were irradiated before the beam test using the cyclotron facility of the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS) to induce radation damage to the sensor. Measurements at different operating points (thresholds, bias voltages) provide important information about cluster-shape frequencies, needed to tune the ALICE Monte-Carlo generators. Very good agreement between test-beam data and simulations is obtained.
{"title":"Characterization of ALPIDE silicon sensors with inclined tracks","authors":"S. Kushpil","doi":"10.22323/1.390.0805","DOIUrl":"https://doi.org/10.22323/1.390.0805","url":null,"abstract":"The upgrade of the ALICE Inner Tracking System (ITS) aims at improving the capabilities of ALICE in terms of read-out rate as well as track pointing resolution and track finding efficiency, especially for particles with low transverse momenta. The new ITS will be a low material budget detector with high granularity and read-out speed. It comprises seven concentric layers of Monolithic Active Pixel Sensors (MAPS) with a total active surface of about 10 m2. The developed MAPS are based on the TowerJazz 180 nm CMOS technology. The sensor is called ALPIDE. In this paper we present the setup used for measurements with inclined tracks and we discuss the sensor efficiency obtained using π beams with a momentum of 6 GeV/c at the Proton Synchrotron (PS) at CERN. Some sensors were irradiated before the beam test using the cyclotron facility of the Nuclear Physics Institute of the Czech Academy of Sciences (NPI CAS) to induce radation damage to the sensor. Measurements at different operating points (thresholds, bias voltages) provide important information about cluster-shape frequencies, needed to tune the ALICE Monte-Carlo generators. Very good agreement between test-beam data and simulations is obtained.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77059851","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}
The Jiangmen Underground Neutrino Observatory (JUNO) is designed to primarily measure the neutrino Mass Ordering (MO) by detecting reactor anti-neutrinos via inverse beta decay. JUNO also has other rich physical potentials. Its Central Detector (CD), which is an acrylic sphere with a diameter of 35.4 m, filled by approximately 20 kton of liquid scintillator (LS), is equipped with large photomultipliers (18k for the CD + 2k for the Water Pool) and small photomultipliers (25,600) to measure the energy resolution of neutrinos with an unprecedented energy resolution of 3%/ E and an energy non-linearity better than 1%. Accordingly, a calibration complex, including Automatic Calibration Unit (ACU), Cable Loop System (CLS), Guide Tube Calibration System (GTCS) and Remotely Operated under-liquid-scintillator Vehicles (ROV), is designed to deliver multiple radioactive sources for the energy coverage of reactor neutrinos and CD full-volume. In this proceeding, the new design details and up-to-date progress about JUNO calibration system are presented.
{"title":"The JUNO Calibration Strategy and Simulation","authors":"Kangfu Zhu, Qingmin Zhang","doi":"10.22323/1.390.0817","DOIUrl":"https://doi.org/10.22323/1.390.0817","url":null,"abstract":"The Jiangmen Underground Neutrino Observatory (JUNO) is designed to primarily measure the neutrino Mass Ordering (MO) by detecting reactor anti-neutrinos via inverse beta decay. JUNO also has other rich physical potentials. Its Central Detector (CD), which is an acrylic sphere with a diameter of 35.4 m, filled by approximately 20 kton of liquid scintillator (LS), is equipped with large photomultipliers (18k for the CD + 2k for the Water Pool) and small photomultipliers (25,600) to measure the energy resolution of neutrinos with an unprecedented energy resolution of 3%/ E and an energy non-linearity better than 1%. Accordingly, a calibration complex, including Automatic Calibration Unit (ACU), Cable Loop System (CLS), Guide Tube Calibration System (GTCS) and Remotely Operated under-liquid-scintillator Vehicles (ROV), is designed to deliver multiple radioactive sources for the energy coverage of reactor neutrinos and CD full-volume. In this proceeding, the new design details and up-to-date progress about JUNO calibration system are presented.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80629584","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}
With the explosion of the number of distributed applications, a new dynamic server environment emerged grouping servers into clusters, utilization of which depends on the current demand for the application. To provide reliable and smooth services it is crucial to detect and fix possible erratic behavior of individual servers in these clusters. Use of standard techniques for this purpose requires manual work and delivers sub-optimal results. Using only application agnostic monitoring metrics our machine learning based method analyzes the recent performance of the inspected server as well as the state of the rest of the cluster, thus checking not only the behavior of the single server, but the load on the whole distributed application as well. We have implemented our method in a Spark job running in the CERN MONIT infrastructure. In this contribution we present results of testing multiple machine learning algorithms and pre-processing techniques to identify the servers erratic behavior. We also discuss the challenges of deploying our new method into production.
{"title":"Erratic server behavior detection using machine learning on basic monitoring metrics","authors":"M. Adam, L. Magnoni, D. Adamová","doi":"10.22323/1.390.0899","DOIUrl":"https://doi.org/10.22323/1.390.0899","url":null,"abstract":"With the explosion of the number of distributed applications, a new dynamic server environment emerged grouping servers into clusters, utilization of which depends on the current demand for the application. To provide reliable and smooth services it is crucial to detect and fix possible erratic behavior of individual servers in these clusters. Use of standard techniques for this purpose requires manual work and delivers sub-optimal results. Using only application agnostic monitoring metrics our machine learning based method analyzes the recent performance of the inspected server as well as the state of the rest of the cluster, thus checking not only the behavior of the single server, but the load on the whole distributed application as well. We have implemented our method in a Spark job running in the CERN MONIT infrastructure. In this contribution we present results of testing multiple machine learning algorithms and pre-processing techniques to identify the servers erratic behavior. We also discuss the challenges of deploying our new method into production.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87714979","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. A. Hernandez-ruiz, Muhammet Köksal, A. Billur, A. Gutiérrez-Rodríguez
M. A. Hernández-Ruíz,0,∗ M. Köksal, A. A. Billur and A. Gutiérrez-Rodríguez. Unidad Académica de Ciencias Químicas, Universidad Autónoma de Zacatecas Apartado Postal 585, 98060 Zacatecas, México. Deparment of Optical Engineering, Sivas Cumhuriyet University 58140, Sivas, Turkey. Deparment of Physics, Sivas Cumhuriyet University 58140, Sivas, Turkey. Unidad Académica de Física, Universidad Autónoma de Zacatecas Apartado Postal C-580, 98060 Zacatecas, México. E-mail: mahernan@uaz.edu.mx, mkoksal@cumhuriyet.edu.tr,
M. A. hernandez - ruiz,0，∗M. koksal, A. A. Billur和A. gutierrez - rodriguez。萨卡特卡斯自治大学化学科学学术单位，Apartado Postal 585, 98060萨卡特卡斯，墨西哥。土耳其Sivas Cumhuriyet大学光学工程系58140。= =地理= =根据美国人口普查，该镇的土地面积为。学术单位物理，萨卡特卡斯自治大学Apartado Postal C-580, 98060萨卡特卡斯，墨西哥。电子邮件:mahernan@uaz.edu.mx, mkoksal@cumhuriyet.edu.tr，
{"title":"Probing the prospective FCC-he sensitivities on the electromagnetic dipole moments of the top-quark","authors":"M. A. Hernandez-ruiz, Muhammet Köksal, A. Billur, A. Gutiérrez-Rodríguez","doi":"10.22323/1.390.0353","DOIUrl":"https://doi.org/10.22323/1.390.0353","url":null,"abstract":"M. A. Hernández-Ruíz,0,∗ M. Köksal, A. A. Billur and A. Gutiérrez-Rodríguez. Unidad Académica de Ciencias Químicas, Universidad Autónoma de Zacatecas Apartado Postal 585, 98060 Zacatecas, México. Deparment of Optical Engineering, Sivas Cumhuriyet University 58140, Sivas, Turkey. Deparment of Physics, Sivas Cumhuriyet University 58140, Sivas, Turkey. Unidad Académica de Física, Universidad Autónoma de Zacatecas Apartado Postal C-580, 98060 Zacatecas, México. E-mail: mahernan@uaz.edu.mx, mkoksal@cumhuriyet.edu.tr,","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84046158","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}
The Alpha Magnetic Spectrometer is a general-purpose particle physics detector operating on the International Space Station. Precision measurements by AMS of the cosmic-ray elementary particle fluxes and nuclei fluxes reveal new unexpected phenomena. The positron flux exhibits a significant excess starting from 25.2 ± 1.8GeV followed by a sharp drop-off above 284+91 −64 GeV, consistent with a primary source of cosmic-ray positrons from either dark matter collisions or new astrophysical sources. The different behavior of the cosmic-ray electron flux and positron flux shows that most high energy electrons originate from different sources than high energy positrons. Intriguingly, the positron flux and the antiproton flux have strikingly similar behavior at high energies. New observations from AMS on cosmic nuclei show that primary cosmic-ray He, C, and O have an identical rigidity dependence above 60 GV and deviate from a single powerlaw above 200 GV. Unexpectedly, the primary Ne, Mg, and Si also have an identical rigidity dependence above 86.5 GV, but they are different from that of He, C, and O. This shows that primary cosmic rays have at least two distinct classes of rigidity dependence. Above 30 GV, secondary cosmic nuclei Li, Be, and B have identical rigidity dependence which is distinctly different from those of primary cosmic rays. The results from AMS on many different types of cosmic rays are not explained by the current theoretical models and provide unique input to the understanding of the origins and evolution of cosmic rays in the galaxy.
{"title":"Latest Results from the AMS Experiment on the International Space Station","authors":"Z. Weng","doi":"10.22323/1.390.0045","DOIUrl":"https://doi.org/10.22323/1.390.0045","url":null,"abstract":"The Alpha Magnetic Spectrometer is a general-purpose particle physics detector operating on the International Space Station. Precision measurements by AMS of the cosmic-ray elementary particle fluxes and nuclei fluxes reveal new unexpected phenomena. The positron flux exhibits a significant excess starting from 25.2 ± 1.8GeV followed by a sharp drop-off above 284+91 −64 GeV, consistent with a primary source of cosmic-ray positrons from either dark matter collisions or new astrophysical sources. The different behavior of the cosmic-ray electron flux and positron flux shows that most high energy electrons originate from different sources than high energy positrons. Intriguingly, the positron flux and the antiproton flux have strikingly similar behavior at high energies. New observations from AMS on cosmic nuclei show that primary cosmic-ray He, C, and O have an identical rigidity dependence above 60 GV and deviate from a single powerlaw above 200 GV. Unexpectedly, the primary Ne, Mg, and Si also have an identical rigidity dependence above 86.5 GV, but they are different from that of He, C, and O. This shows that primary cosmic rays have at least two distinct classes of rigidity dependence. Above 30 GV, secondary cosmic nuclei Li, Be, and B have identical rigidity dependence which is distinctly different from those of primary cosmic rays. The results from AMS on many different types of cosmic rays are not explained by the current theoretical models and provide unique input to the understanding of the origins and evolution of cosmic rays in the galaxy.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91225831","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}
We show that it is possible to reduce the size of a classification problem by automatically ranking the relative importance of available features. Variables are importance-sorted with a decision tree algorithm and correlated ones are removed after ranking. The selected features can be used as input quantities for the classification problem at hand. We tested the method with the case of highly boosted di-jet resonances decaying to two 1-quarks, to be selected against an overwhelming QCD background with a Deep Neural network. We make it explicit the relation between different importance rankings obtained with different algorithms. We also show how the signal-to-background ratio changes, varying the number of features to feed the Neural Network with.
{"title":"Automated selection of particle-jet features for data analysis in High Energy Physics experiments","authors":"A. Luca, F. Follega, M. Cristoforetti, R. Iuppa","doi":"10.22323/1.390.0907","DOIUrl":"https://doi.org/10.22323/1.390.0907","url":null,"abstract":"We show that it is possible to reduce the size of a classification problem by automatically ranking the relative importance of available features. Variables are importance-sorted with a decision tree algorithm and correlated ones are removed after ranking. The selected features can be used as input quantities for the classification problem at hand. We tested the method with the case of highly boosted di-jet resonances decaying to two 1-quarks, to be selected against an overwhelming QCD background with a Deep Neural network. We make it explicit the relation between different importance rankings obtained with different algorithms. We also show how the signal-to-background ratio changes, varying the number of features to feed the Neural Network with.","PeriodicalId":20428,"journal":{"name":"Proceedings of 40th International Conference on High Energy physics — PoS(ICHEP2020)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78499862","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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