{"id":{"repo_id":"iu","oai_identifier":"oai:scholarworks.iu.edu:2022/20936"},"canonical_url":"https://search.dev.ndltd.org/etd/iu/oai:scholarworks.iu.edu:2022/20936","repository":{"repo_id":"iu","name":"Indiana University","base_url":"https://scholarworks.iu.edu/iuswrrest/oai/request"},"display":{"title":"Evidence for e+e− → γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV at BESIII","abstract":"This dissertation shows the first evidence of the process e+e− → γηc(1S) using data collected by the BESIII experiment operating at BEPCII. This process can be used as a probe to study the nature of recently discovered charmonium-like Y states between 4.0 and 4.6 GeV, including the Y (4260) and Y (4360). Data collected at six center-of-mass energies are analyzed, namely: 4.01, 4.23, 4.26, 4.36, 4.42, and 4.60 GeV, corresponding to a total integrated luminosity of 4.6 fb−1. We measure the Born cross section, σE(e+e− → γηc(1S)), at each energy using a combination of twelve ηc(1S) decay channels. Because the significance of the signal is marginal at each energy (≤ 3.0σ), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If a Y (4260) is assumed, we measure σ4.26(e+e− → γηc(1S)) = 2.11 ± 0.49(stat.) ± 0.33(syst.) pb with a significance of 4.2σ. With our current statistics we are unable to distinguish the Y (4260) process from others.","abstract_html":"This dissertation shows the first evidence of the process e+e− → γηc(1S) using data collected by the BESIII experiment operating at BEPCII. This process can be used as a probe to study the nature of recently discovered charmonium-like Y states between 4.0 and 4.6 GeV, including the Y (4260) and Y (4360). Data collected at six center-of-mass energies are analyzed, namely: 4.01, 4.23, 4.26, 4.36, 4.42, and 4.60 GeV, corresponding to a total integrated luminosity of 4.6 fb−1. We measure the Born cross section, σE(e+e− → γηc(1S)), at each energy using a combination of twelve ηc(1S) decay channels. Because the significance of the signal is marginal at each energy (≤ 3.0σ), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If a Y (4260) is assumed, we measure σ4.26(e+e− → γηc(1S)) = 2.11 ± 0.49(stat.) ± 0.33(syst.) pb with a significance of 4.2σ. With our current statistics we are unable to distinguish the Y (4260) process from others.","abstract_has_math":false,"creators":["Lara, Manuel"],"institution":"[Bloomington, Ind.] : Indiana University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Mitchell, Ryan","Shepherd, Matthew"],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-07","date_published":"2016-07","updated_at":"2026-07-24T02:40:00Z","subjects":["Particle physics","Decays of Y","Radiative decays of mesons"],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2022/20936","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Mitchell, Ryan","Shepherd, Matthew"]},{"key":"dc:creator","label":"Author","values":["Lara, Manuel"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-08-03T17:50:36Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-08-03T17:50:36Z"]},{"key":"dc:date.issued","label":"Date","values":["2016-07"]},{"key":"dc:publisher","label":"Institution","values":["[Bloomington, Ind.] : Indiana University"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Particle physics","Decays of Y","Radiative decays of mesons"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2022/20936"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This dissertation shows the first evidence of the process e+e− → γηc(1S) using data collected by the BESIII experiment operating at BEPCII. This process can be used as a probe to study the nature of recently discovered charmonium-like Y states between 4.0 and 4.6 GeV, including the Y (4260) and Y (4360). Data collected at six center-of-mass energies are analyzed, namely: 4.01, 4.23, 4.26, 4.36, 4.42, and 4.60 GeV, corresponding to a total integrated luminosity of 4.6 fb−1. We measure the Born cross section, σE(e+e− → γηc(1S)), at each energy using a combination of twelve ηc(1S) decay channels. Because the significance of the signal is marginal at each energy (≤ 3.0σ), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If a Y (4260) is assumed, we measure σ4.26(e+e− → γηc(1S)) = 2.11 ± 0.49(stat.) ± 0.33(syst.) pb with a significance of 4.2σ. With our current statistics we are unable to distinguish the Y (4260) process from others."]},{"key":"dc:title","label":"Title","values":["Evidence for e+e− → γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV at BESIII"]}]}],"canonical_facts":{"dc:contributor.advisor":["Mitchell, Ryan","Shepherd, Matthew"],"dc:creator":["Lara, Manuel"],"dc:date.accessioned":["2016-08-03T17:50:36Z"],"dc:date.available":["2016-08-03T17:50:36Z"],"dc:date.issued":["2016-07"],"dc:description.abstract":["This dissertation shows the first evidence of the process e+e− → γηc(1S) using data collected by the BESIII experiment operating at BEPCII. This process can be used as a probe to study the nature of recently discovered charmonium-like Y states between 4.0 and 4.6 GeV, including the Y (4260) and Y (4360). Data collected at six center-of-mass energies are analyzed, namely: 4.01, 4.23, 4.26, 4.36, 4.42, and 4.60 GeV, corresponding to a total integrated luminosity of 4.6 fb−1. We measure the Born cross section, σE(e+e− → γηc(1S)), at each energy using a combination of twelve ηc(1S) decay channels. Because the significance of the signal is marginal at each energy (≤ 3.0σ), we also combine all six energies under various assumptions for the energy-dependence of the cross section. If a Y (4260) is assumed, we measure σ4.26(e+e− → γηc(1S)) = 2.11 ± 0.49(stat.) ± 0.33(syst.) pb with a significance of 4.2σ. With our current statistics we are unable to distinguish the Y (4260) process from others."],"dc:identifier.uri":["https://hdl.handle.net/2022/20936"],"dc:language.iso":["en_US"],"dc:publisher":["[Bloomington, Ind.] : Indiana University"],"dc:subject":["Particle physics","Decays of Y","Radiative decays of mesons"],"dc:title":["Evidence for e+e− → γηc(1S) at center-of-mass energies between 4.01 and 4.60 GeV at BESIII"],"dc:type":["Doctoral Dissertation"]},"updated_at":"2026-07-24T02:40:00Z"}