{"title":"Probing new physics with τ-leptons at the LHC","authors":"German Valencia","doi":"10.1016/j.nuclphysbps.2014.09.043","DOIUrl":"10.1016/j.nuclphysbps.2014.09.043","url":null,"abstract":"<div><p>We discuss new physics that can show up in the <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> production process at the LHC but not in the dimuon or the dielectric channels. We consider three different generic possibilities: a new resonance in the Drell-Yan process in the form of a non-universal <span><math><msup><mrow><mi>Z</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>; a new non-resonant contribution to <span><math><mi>q</mi><mover><mi>q</mi><mo>¯</mo></mover><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> in the form of leptoquarks; and contributions from gluon fusion due to effective lepton gluonic couplings. We emphasize the use of the charge asymmetry both to discover new physics and to distinguish between different possibilities</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86039799","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":"Status of Leading-Order Hadronic Vacuum Polarization Dispersion Calculation","authors":"Zhiqing Zhang","doi":"10.1016/j.nuclphysbps.2014.09.032","DOIUrl":"10.1016/j.nuclphysbps.2014.09.032","url":null,"abstract":"<div><p>The leading-order hadronic contribution to the muon magnetic anomaly <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>≡</mo><mo>(</mo><msub><mrow><mi>g</mi></mrow><mrow><mi>μ</mi></mrow></msub><mo>−</mo><mn>2</mn><mo>)</mo><mo>/</mo><mn>2</mn></math></span>, calculated using a dispersion integral of <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> annihilation data and <em>τ</em> decay data, is briefly reviewed. This contribution has the largest uncertainty to the predicted value of <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span>, which differs from the experimental value by ∼ 3.6 (2.4) standard deviations for the <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> (<em>τ</em>) based analysis. New results since the last workshop and main open issues on the subject are discussed.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90542803","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 the Standard Model Higgs Boson in the H to τ+τ− to lepton-hadron and hadron-hadron Decay Modes with the ATLAS Detector","authors":"Yuki Sakurai, ATLAS Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.061","DOIUrl":"10.1016/j.nuclphysbps.2014.09.061","url":null,"abstract":"<div><p>In this proceeding, a search for a Higgs boson in the H to <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> decay mode, where both taus decay hadronically or one decay hadronically and one leptonically. The analysis is based on a data sample of proton-proton collision collected by the ATLAS detector at the Large Hadron Collider (LHC) at centre-of-mass energies of 7 TeV during 2011, corresponding to an integrated luminosity of <span><math><mn>4.7</mn><mi>f</mi><msup><mrow><mi>b</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>. No significant excess is observed in the Higgs boson mass range of 100–150 GeV. The observed (expected) limits on the cross-section times branching ratio for H to <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> at <span><math><msub><mrow><mi>m</mi></mrow><mrow><mi>H</mi></mrow></msub><mo>=</mo><mn>125</mn><mtext> GeV</mtext></math></span> are 6.2(5.9) and 6.3(6.5) for lepton-hadron and hadron-hadron decay modes, respectively.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.061","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"108451816","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":"CP Violation in τ Decays at SuperB & Belle II Experiments – like Finding Signs of Dark Matter","authors":"I.I. Bigi","doi":"10.1016/j.nuclphysbps.2014.09.022","DOIUrl":"10.1016/j.nuclphysbps.2014.09.022","url":null,"abstract":"<div><p>BaBar has found <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>CP</mi></mrow></msub><mo>(</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><mi>ν</mi><msub><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow></msub><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>[</mo><mo>≥</mo><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>]</mo><mo>)</mo><mo>=</mo><mo>(</mo><mo>−</mo><mn>0.36</mn><mo>±</mo><mn>0.23</mn><mo>±</mo><mn>0.11</mn><mo>)</mo><mtext>%</mtext></math></span> with 2.8 <em>σ</em> difference with SM prediction <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>CP</mi></mrow></msub><mo>(</mo><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><mi>ν</mi><msub><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow></msub><msup><mrow><mi>π</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>)</mo><mo>=</mo><mo>(</mo><mn>0.36</mn><mo>±</mo><mn>0.01</mn><mo>)</mo><mtext>%</mtext></math></span> based on <span><math><msup><mrow><mi>K</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>−</mo><msup><mrow><mover><mi>K</mi><mo>¯</mo></mover></mrow><mrow><mn>0</mn></mrow></msup></math></span> oscillation. Four central points: (i) to establish both the ‘existence’ of New Dynamics (ND) and its ‘features’ in local CP asymmetries; (ii) to increase the number of final states to be probed; (iii) to emphasize correlations of CP violations between different final states; (iv) likewise for the correlations with <span><math><msup><mrow><mi>D</mi></mrow><mrow><mo>±</mo></mrow></msup></math></span> final states. These measurements should be possible at SuperB & Belle II experiments.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"112086170","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 mu LFV from MEG","authors":"H. Natori, MEG collaboration","doi":"10.1016/j.nuclphysbps.2014.09.007","DOIUrl":"10.1016/j.nuclphysbps.2014.09.007","url":null,"abstract":"<div><p>The MEG experiment searches for a lepton flavor violating muon decay, <span><math><mi>μ</mi><mo>→</mo><mi>e</mi><mi>γ</mi></math></span>, discovery of which gives a clear evidence of the new physics beyond the Standard Model of the elementary particle physics. By analyzing the data taken in 2009 and 2010, which corresponds to 1.8 × 10<sup>14</sup> muon decays in the stopping target, the result was consistent with null signal. The most stringent upper limit on the branching ratio of 2.4 × 10<sup>−12</sup> is set.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"108451736","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":"Measurement of τ Polarization in W→τν Decays with the ATLAS Detector in pp Collisions at s=7TeV","authors":"Zofia Czyczula, ATLAS collaboration","doi":"10.1016/j.nuclphysbps.2014.09.044","DOIUrl":"10.1016/j.nuclphysbps.2014.09.044","url":null,"abstract":"<div><p>In this proceedings, the first measurement of <em>τ</em> polarization at a hadron collider is presented. The method for extracting the <em>τ</em> polarization is independent of the mode of <em>τ</em> production and can be applied to the characterization of new phenomena at the Large Hadron Collider. The method has been applied to <span><math><mi>W</mi><mo>→</mo><mi>τ</mi><mi>ν</mi></math></span> decays and the measured value of <span><math><msub><mrow><mi>P</mi></mrow><mrow><mi>τ</mi></mrow></msub><mo>=</mo><mo>−</mo><mn>1.06</mn><mo>±</mo><mn>0.04</mn><mspace></mspace><msubsup><mrow><mtext><mtext>(</mtext><mi>stat</mi><mtext>)</mtext></mtext></mrow><mrow><mo>−</mo><mn>0.07</mn></mrow><mrow><mo>+</mo><mn>0.05</mn></mrow></msubsup><mspace></mspace><mtext><mtext>(</mtext><mi>syst</mi><mtext>)</mtext></mtext></math></span> is in agreement with the Standard Model prediction.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113596700","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 Light and Dark Higgs at BaBar","authors":"Swagato Banerjee, BaBar Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.005","DOIUrl":"10.1016/j.nuclphysbps.2014.09.005","url":null,"abstract":"<div><p>In many new physics extensions of the Standard Model, light pseudoscalar Higgs or dark matter candidates naturally appear. Searches for light and dark Higgs bosons performed with the large <span><math><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> datasets collected by the <em>BaBar</em> experiment at center-of-mass energies around the ϒ resonances are presented.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"109428082","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":"Tau Decays in Pythia 8","authors":"Philip Ilten","doi":"10.1016/j.nuclphysbps.2014.09.019","DOIUrl":"10.1016/j.nuclphysbps.2014.09.019","url":null,"abstract":"<div><p>As of version 8.150 of <span>Pythia</span>, the isotropic decay model of <em>τ</em>-leptons has been replaced with sophisticated <em>τ</em>-lepton decay machinery. The decays and spin correlations for <em>τ</em>-leptons in <span>Pythia</span> 8 are described, including the spin correlation algorithm, the available <em>τ</em>-lepton production processes, the <em>τ</em>-lepton decay models, the user interface, and the implementation.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"111867281","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":"Reactor θ13 Results and Recent Results from FNAL Neutrino Experiments","authors":"R.A. Johnson","doi":"10.1016/j.nuclphysbps.2014.09.037","DOIUrl":"10.1016/j.nuclphysbps.2014.09.037","url":null,"abstract":"<div><p>The past year has been very exciting for neutrino physics. The last mixing angle, <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mn>13</mn></mrow></msub></math></span>, has been measured by a number of experiments and is quite large. These experiments will, hopefully, continue reducing systematic and statistical errors in anticipation of statistically significant CP violation experiments. At Fermilab, MiniBooNE has finished its data run and has new results for electron antineutrino excesses; MINOS has done a combined fit for their <span><math><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub></math></span> disappearance measurements for neutrinos and antineutrinos (which are now consistent) and presented results for a sterile neutrino search; and Miner<em>ν</em>a has presented its first cross section results.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"109726807","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 neutral MSSM Higgs Bosons in the h/A/H to τ+τ− Decay Mode with the ATLAS Detector","authors":"Takashi Mitani, ATLAS Collaboration","doi":"10.1016/j.nuclphysbps.2014.09.058","DOIUrl":"10.1016/j.nuclphysbps.2014.09.058","url":null,"abstract":"<div><p>In these proceedings a search for neutral Higgs bosons in the Minimal Supersymmetric Standard Model in the decay modes h/A/H to <span><math><msup><mrow><mi>τ</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>τ</mi></mrow><mrow><mo>−</mo></mrow></msup></math></span> is reported. This search is performed using 4.7 fb<sup>−1</sup> of integrated luminosity of <em>pp</em> collision data collected at the Large Hadron Collider at <span><math><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>7</mn><mtext> TeV</mtext></math></span> during 2011. Upper limits on the cross-section times branching ratio, for both <em>b</em>-associated and gluon-fusion production modes, are derived for the Higgs mass range of 90–500 GeV. Exclusion limits are also shown in the <span><math><msub><mrow><mi>m</mi></mrow><mrow><mi>A</mi></mrow></msub><mo>−</mo><mi>tan</mi><mo></mo><mi>β</mi></math></span> plane for the <span><math><msubsup><mrow><mi>m</mi></mrow><mrow><mi>h</mi></mrow><mrow><mi>max</mi></mrow></msubsup></math></span> scenario with <span><math><mi>μ</mi><mo>></mo><mn>0</mn></math></span>.</p></div>","PeriodicalId":93343,"journal":{"name":"Nuclear physics. B, Proceedings, supplements","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.nuclphysbps.2014.09.058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"112897562","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}