{"title":"Measurement of the τ lifetime from Belle","authors":"A.A. Sokolov, Belle Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.021","DOIUrl":"10.1016/j.nuclphysbps.2014.09.021","url":null,"abstract":"<div><p>The lifetime of the <em>τ</em>-lepton is measured using the process <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span>, where both <em>τ</em>-leptons decay to <span><math><mn>3</mn><mi>π</mi><mi>ν</mi></math></span>. The preliminary result based on 711 fb<sup>−1</sup> of data collected on the <span><math><mi>ϒ</mi><mo>(</mo><mn>4</mn><mi>S</mi><mo>)</mo></math></span> resonance and in the nearby continuum is <span><math><msub><mrow><mi>τ</mi></mrow><mrow><mi>τ</mi></mrow></msub><mo>=</mo><mo>(</mo><mn>290.18</mn><mo>±</mo><mn>0.54</mn><mo>(</mo><mtext>stat.</mtext><mo>)</mo><mo>±</mo><mn>0.33</mn><mo>(</mo><mtext>syst.</mtext><mo>)</mo><mo>)</mo><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>15</mn></mrow></msup><mtext> s</mtext></math></span>.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 87-90"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.021","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113797568","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}
A. Gutiérrez-Rodríguez , M.A. Hernández-Ruíz , C.P. Castañeda-Almanza , A. Espinoza-Garrido , A. Chubykalo
{"title":"Limits on the electromagnetic and weak dipole moments of the tau-lepton in a 331 model","authors":"A. Gutiérrez-Rodríguez , M.A. Hernández-Ruíz , C.P. Castañeda-Almanza , A. Espinoza-Garrido , A. Chubykalo","doi":"10.1016/j.nuclphysbps.2014.09.049","DOIUrl":"10.1016/j.nuclphysbps.2014.09.049","url":null,"abstract":"<div><p>Using as an input the data obtained by the L3 and OPAL Collaborations for the reaction <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>γ</mi></math></span> at the <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>-pole, we obtained bounds on the electromagnetic and weak dipole moments of the tau-lepton in the context of a 331 model. Our bounds on the electromagnetic moments are consistent with the bounds obtained by the L3 and OPAL Collaborations for the reaction <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mi>γ</mi></math></span>. We also obtained bounds on the tau weak dipole moments which are consistent with the bounds obtained recently by the DELPHI, ALEPH and BELLE Collaborations from the reaction <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span>. Our work complements other studies on the electromagnetic and weak dipole moments of the tau-lepton.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 202-203"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"107689362","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 Ultra-High Energy Tau Neutrinos in IceCube","authors":"Dawn Williams, IceCube Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.038","DOIUrl":"10.1016/j.nuclphysbps.2014.09.038","url":null,"abstract":"<div><p>The IceCube Neutrino Observatory at the geographic South Pole was designed with the primary goal of discovering high energy neutrinos from astrophysical objects such as active galactic nuclei and gamma ray bursts. IceCube completed construction in 2010 and has been collecting data throughout the construction phase. IceCube is sensitive to all three flavors of neutrinos, each of which has a distinct topological signature within the detector. At sufficiently high energies, the tau neutrino signature is a “double bang” from the charged current interaction of the neutrino and the decay of the tau lepton. At high energies, the tau neutrino has negligible background and would be an intriguing astrophysical signature. A dedicated search for ultra-high energy tau neutrinos (340 TeV–200 PeV) was performed using data from the partial IceCube detector, yielding a 90% CL upper limit of <span><math><msubsup><mrow><mi>E</mi></mrow><mrow><mi>ν</mi></mrow><mrow><mn>2</mn></mrow></msubsup><msub><mrow><mi>Φ</mi></mrow><mrow><mn>90</mn></mrow></msub><mo>(</mo><msub><mrow><mi>ν</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>)</mo><mo><</mo><mn>16.3</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>8</mn></mrow></msup><mspace></mspace><mtext>GeV</mtext><mspace></mspace><msup><mrow><mtext>cm</mtext></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>sr</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>s</mtext></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> on a diffuse astrophysical flux of UHE neutrinos.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 155-158"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"94903219","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":"Updating quantum electro-dynamical (QED) contribution to the muon g−2","authors":"Masashi Hayakawa","doi":"10.1016/j.nuclphysbps.2014.09.031","DOIUrl":"10.1016/j.nuclphysbps.2014.09.031","url":null,"abstract":"<div><p>I first recall the relevance of the eighth-order and the tenth-order QED contributions to the muon <span><math><mi>g</mi><mo>−</mo><mn>2</mn></math></span> in order to interpret the results to be obtained in the next-generation experiment of the muon <span><math><mi>g</mi><mo>−</mo><mn>2</mn></math></span>. We give the latest result of the numerical calculation of those contributions.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 127-130"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"97593638","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":"OPERA Results","authors":"Osamu Sato, OPERA Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.036","DOIUrl":"https://doi.org/10.1016/j.nuclphysbps.2014.09.036","url":null,"abstract":"<div><p>The aim of OPERA is to prove the existence of the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>→</mo><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></math></span> neutrino oscillation by detecting the <em>τ</em> lepton emitted in the <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></math></span> CC interactions. Thanks to the sub-micron resolution of the emulsion technique, the <em>τ</em> decay topology is clearly identified. The accumulated number of neutrino events in the OPERA target until mid-September 2012 is about 16000. Among the sample of 4190 events analysed so-far, two candidate <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></math></span> CC interactions have been identified. The first one was published in May 2010 and the second one was recently reported at the NEUTRINO 2012 conference in June 2012.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 147-150"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138387084","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":"Lepton number violation in tau lepton decays","authors":"G. López Castro, N. Quintero","doi":"10.1016/j.nuclphysbps.2014.09.004","DOIUrl":"10.1016/j.nuclphysbps.2014.09.004","url":null,"abstract":"<div><p>Recent studies of novel four-body lepton number violating decays of <em>τ</em> leptons and neutral <em>B</em> mesons are summarized and updated. These decays are assumed to be enhanced by the exchange of resonant Majorana neutrinos. It is shown that the <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>π</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>l</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>l</mi></mrow><mrow><mo>−</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>τ</mi></mrow></msub></math></span> decay channels, with <span><math><mi>l</mi><mo>=</mo><mi>e</mi></math></span> or <em>μ</em>, can provide stronger constraints on the mixing vs. mass parameter space of resonant Majorana neutrinos than analogous three-body decays of charged <em>B</em> mesons.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 12-15"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86737125","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":"Dispersive evaluation of the second-class amplitude τ→ηπντ in the standard model","authors":"S. Descotes-Genon , E. Kou , B. Moussallam","doi":"10.1016/j.nuclphysbps.2014.09.016","DOIUrl":"10.1016/j.nuclphysbps.2014.09.016","url":null,"abstract":"<div><p>We reevaluate the two form factors relevant for the <em>ηπ</em> second-class <em>τ</em> decay mode, making systematic use of analyticity, unitarity, combined with updated inputs to the NLO chiral constraints. We focus in particular on the shape of the <em>ρ</em> resonance peak which is a background-free signature of a second-class current. Its dispersive construction requires the <span><math><mi>η</mi><mi>π</mi><mo>→</mo><mi>π</mi><mi>π</mi></math></span> scattering amplitude which we derive from a family of Khuri-Treiman equations solutions constrained with accurate recent results on the <span><math><mi>η</mi><mo>→</mo><mn>3</mn><mi>π</mi></math></span> Dalitz plot.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 65-68"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77896526","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":"New Positron Spectrometer for MEG Experiment Upgrade","authors":"M. Nishimura, MEG collaboration","doi":"10.1016/j.nuclphysbps.2014.09.060","DOIUrl":"10.1016/j.nuclphysbps.2014.09.060","url":null,"abstract":"<div><p>An upgrade of the MEG experiment, which searches for the lepton flavor violating decay, <span><math><mi>μ</mi><mo>→</mo><mi>e</mi><mi>γ</mi></math></span>, at the highest sensitivity ever, is planned in order to improve the sensitivity down to <span><math><mo>∼</mo><mn>5</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup></math></span>. We plan to employ a stereo wire drift chamber with a unique volume for the tracking and a pixelated scintillation detector with silicon photomultiplier (SiPM) readout for the timing measurement with improved efficiency and resolutions. We will describe the expected performance and the R&D status of the new spectrometer especially focusing on the new timing counter, which is expected to contribute better resolution of the relative timing between positron and gamma-ray.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 224-225"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"99576728","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":"Upgrade of LXe gamma-ray detector in MEG experiment","authors":"Daisuke Kaneko, MEG collaboration","doi":"10.1016/j.nuclphysbps.2014.09.055","DOIUrl":"10.1016/j.nuclphysbps.2014.09.055","url":null,"abstract":"<div><p>We are searching for the <span><math><mi>μ</mi><mo>→</mo><mi>e</mi><mo>+</mo><mi>γ</mi></math></span> in the MEG experiment. In order to improve the search sensitivity down to about 5 × 10<sup>−14</sup>, which is one order higher than the sensitivity goal of the current stage of the experiment. We are planning a major upgrade of the experiment including the upgrade of the liquid xenon (LXe) <em>γ</em>-ray detector. The main item of the upgrade of the xenon detector is a replacement of the current PMTs located on the <em>γ</em>-ray incident face with smaller photosensors such as MPPC. The energy and position resolutions are expected to be significantly improved, especially for the event where <em>γ</em>-ray converts at a shallow point in the LXe. Because the MPPC operational in liquid xenon is not yet commercially available, we are developing special MPPC in collaboration with Hamamatsu Photonics. The detection efficiency for LXe scintillation light is measured with prototype sensors and found to be already at the level necessary for the upgrade of the experiment.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":"253 ","pages":"Pages 214-215"},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"93113603","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}