{"created":"2023-06-20T13:20:40.488270+00:00","id":711,"links":{},"metadata":{"_buckets":{"deposit":"f56eaa91-f1e9-4ea2-9132-50bad02b75db"},"_deposit":{"created_by":1,"id":"711","owners":[1],"pid":{"revision_id":0,"type":"depid","value":"711"},"status":"published"},"_oai":{"id":"oai:ir.soken.ac.jp:00000711","sets":["2:428:16"]},"author_link":["0","0","0"],"item_1_creator_2":{"attribute_name":"著者名","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"LIU, YANG"}],"nameIdentifiers":[{}]}]},"item_1_creator_3":{"attribute_name":"フリガナ","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"リュウ, ヤン"}],"nameIdentifiers":[{}]}]},"item_1_date_granted_11":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2008-09-30"}]},"item_1_degree_grantor_5":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"総合研究大学院大学"}]}]},"item_1_degree_name_6":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（理学）"}]},"item_1_description_12":{"attribute_name":"要旨","attribute_value_mlt":[{"subitem_description":"　　We study the decay modes of <i>B</i> meson decay to final states including <i>J/ψ</i> and\r\n<i>Φ</i> mesons based on a large amount of data sample at the &upsih;(4S) state collected with\r\nBelle detector in KEKB asymmetric energy <i>e</i><sup>+</sup><i>e</i><sup>-</sup> collider.\r\n　　The decay <i>B</i><sup>0</sup> → <i>J /ψΦ</i></sup> is expected to involve W-exchange and final state interac-\r\ntion (FSI) processes. The mechanisms contributing to this decay can be divided into\r\nfour categories: 1) The photo-production; 2) The tri-gluon fusion; 3) The rescattering<br />effect; 4) The <i>ω - Φ</i> mixing. The dominant contribution is from <i>ω- Φ</i> mixing and the\r\nbranching fraction for this decay is estimated to be (1.8 ± 0.3) × 10<sup>-7</sup>.\r\n　　We perform a search for <i>B</i><sup>0</sup> → <i>J /ψΦ</i> decays using a data sample of 605 fb<sup>-1</sup>\r\n containing 657 × 10<sup>6</sup> <i>BB</i></span>pairs.\r\n　　We reconstruct <i>B</i> mesons from the decays <i>J/ψ</i> → <i>l<sup>+</sup>l<sup>-</sup> (l = e,μ)</i> and <i>Φ</i> →\r\n<i>K<sup>+</sup> K<sup>-</sup></i>. Events are required to pass a basic hadronic event selection. We identify <i>B</i>\r\ncandidates using two widely used kinematic variable calculated in the center-of-mass\r\nsystem:the beam-energy constrained mass (<i>M</i><small>bc</small> &equiv; <big>&radic;</big>E<sup>2</sup><small>beam</small>　―　P<sup>2</sup><small>B</small>) and the energy\r\ndifference (△<i>E</i> &equiv; <i>E<small>B</i></small> - <i>E</i><small>beam</small>), where <i>E</i><small>beam</small> is the beam energy, <i>P<small>B</i></small> and <i>E<small>B</small></i> are the\r\nreconstructed momentum and energy of the B<sup>0</sup> candidate. We select <i>B</i> candidates\r\nwithin the range -0.2 GeV < △<i>E</i> < 0.3 GeV and 5.27 GeV / <i>c</i><sup>2</sup> ＜ <i>M</i><small>bc</small> < 5.29 GeV / <i>c</i><sup>2</sup>\r\nfor final analysis.\r\n　　We study reconstruction efficiency and event selection criteria using a large signal\r\nMonte Calor (MC) sample. To study the background, we use a MC sample corre-\r\nsponding to 3.86 × 10<sup>6</sup>generic <i>BB</i> decays (59 times that of real data) that includes\r\nall known <i>B</i> →　<i>J/ψX</i> processes as well as sideband region.\r\n　　The dominant background comes from <i>BB</i> events with <i>B</i> decays to <i>J/ψ</i>. We\r\n find that the dominant backgrounds come B<sup>0</sup> → <i>J/ψK</i>*<sup>0</sup>(892)[→<i>K</i><sup>-</sup>π<sup>+</sup>] and<br />B<sup>0-</sup> → <i>J/ψK</i><small>1</small>(1270)[→ <i>K</i><sup>-</sup>π<sup>+</sup>π<sup>0/-</sup>]. In both cases, a pion is misidentified as a kaon,\r\nand in the latter case, the other pion is missed. The former has a peak at △<i>E</i> ～0.1～<br />GeV, while the latter has a broad peak in the negative △<i>E</i> region. The remaining\r\nbackground is due to random combinations of <i>J/ψ</i>and <i>Φ</i> candidates and does not\r\nhave structure in the △<i>E</i> distribution (referred to as combinatorial background).\r\n　　The signal yield is extracted by performing an unbinned extended maximum-\r\nlikelihood fit to the △<i>E</i> distribution of candidate events. The signal PDF is mod-\r\neled by a sum of two Gaussians. The background PDFs are two Gaussians for the\r\n<i>J/ψK</i><small>1</small> component, a bifurcated Gaussian for the <i>J/ψK</i><sup>*0</sup> component and a second-\r\norder polynomial for combinatorial background, respectively. The parameters of these\r\nPDFs are determined from MC simulations.\r\n　　We obtain a signal yield of 4.6<sup>+3.1</sup><small>-2.5</small> events with a statistical significance of 2.3σ.\r\nAs no significant signal is found for the <i>B</i><sup>0</sup> →　<i>J /ψΦ</i> decay mode, we an upper\r\nlimit on the yield at the 90% confidence level by a frequentist method using ensembles\r\nof pseudo-experiments. Finally an upper limit at the 90% confidence level is obtained:\r\n\r\n　　　　　　　　　　　　　　<i>β</i>(<i>B</i><sup>0</sup> → <i>J /ψΦ</i>)< 9.4 × 10<sup>-7</sup>.   　　　　　 (1)\r\n\r\n　　This result improves upon the previous result by about a factor of 10 and is\r\nconsistent with the theory prediction. The result shows that a large enhancement\r\n from rescattering is not likely in this decay mode. To check the prediction more\r\nprecisely, a larger data sample is needed.","subitem_description_type":"Other"}]},"item_1_description_7":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"総研大甲第1196号","subitem_description_type":"Other"}]},"item_1_select_14":{"attribute_name":"所蔵","attribute_value_mlt":[{"subitem_select_item":"有"}]},"item_1_select_8":{"attribute_name":"研究科","attribute_value_mlt":[{"subitem_select_item":"高エネルギー加速器科学研究科"}]},"item_1_select_9":{"attribute_name":"専攻","attribute_value_mlt":[{"subitem_select_item":"14 素粒子原子核専攻"}]},"item_1_text_10":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_text_value":"2008"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"LIU, Yang","creatorNameLang":"en"}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1196_要旨.pdf","filesize":[{"value":"252.8 kB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"要旨・審査要旨","url":"https://ir.soken.ac.jp/record/711/files/甲1196_要旨.pdf"},"version_id":"26739eaa-b96c-4fda-815f-96db237e5fca"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-02-17"}],"displaytype":"simple","filename":"甲1196_本文.pdf","filesize":[{"value":"23.0 MB"}],"format":"application/pdf","licensetype":"license_11","mimetype":"application/pdf","url":{"label":"本文","url":"https://ir.soken.ac.jp/record/711/files/甲1196_本文.pdf"},"version_id":"10c4e19f-4c93-4a07-a3c8-3c1f0a6483d5"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Study of B meson decays with J/ψ　and φ in the final states","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Study of B meson decays with J/ψ　and φ in the final states"},{"subitem_title":"Study of B meson decays with J/ψ　and φ in the final states","subitem_title_language":"en"}]},"item_type_id":"1","owner":"1","path":["16"],"pubdate":{"attribute_name":"公開日","attribute_value":"2010-02-22"},"publish_date":"2010-02-22","publish_status":"0","recid":"711","relation_version_is_last":true,"title":["Study of B meson decays with J/ψ　and φ in the final states"],"weko_creator_id":"1","weko_shared_id":1},"updated":"2023-06-20T15:58:08.619836+00:00"}