Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of nu(mu) -> nu(mu) e appearance in data accumulated with 1.43 x 10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Delta m(23)(2)| = 2.4 x 10(-3) eV(2), sin(2)2 theta(23) = 1 and sin(2)2 theta(13) = 0, the expected number of such events is 1.5 +/- 0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7 x 10(-3), equivalent to 2.5 sigma significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2 theta(13) < 0.28(0.34) for delta(CP) = 0 and a normal (inverted) hierarchy

Constraining the T2K neutrino oscillation parameter results using data from the off-axis near detector, ND280 : Implementation of a nucleon removal energy systematic uncertainty treatment in the BANFF fit

Presented in this thesis are the results of the BANFF near-detector fit as part of the T2K 2020 neutrino oscillation parameter constraint, with a focus on the implementation of four nucleon-removal energy parameters, $\Delta E_{\mathrm{rmv}}$. These parameters correspond to the systematic uncertainty associated with the energetic cost, $E_{\mathrm{rmv}}$, of liberating a bound nucleon from the ground state of a nucleus in quasielastic neutrino scattering. Previously the dominant source of systematic uncertainty on the extraction of the neutrino mass splitting term $\Delta m^2_{32}$(NO)/$|\Delta m^2_{31}|$(IO), an update of the nuclear model used for CCQE interactions at T2K from a relativistic Fermi gas model to a spectral function model and a new treatment of the systematic uncertainty on $E_{\mathrm{rmv}}$ has allowed the total bias on $\Delta m^2_{32}$ to be reduced by a factor of 2.8, and does not impact T2K's ability to exclude leptonic CP-conservation. The fit to the ND280 data is an essential stage of the extraction of the PMNS mixing parameters from T2K's data in which the beam and interaction cross-section models common to ND280 and Super-Kamiokande are constrained by sampling the unoscillated beam. The ND280 data are shown to be consistent with the T2K model, reporting a p-value of $p=0.74$, an improvement on the previous ND280 fit $p=0.5$. A study of the postfit model shows an improved consistency with a p-value of $p=0.82$. The impact of propagating biases in the fits to the ND280 data to the fits to Super-Kamiokande data on the constraints on $\Delta m^2_{32}$ and $\delta_{CP}$ are investigated, shown to be small, and covered by an additional uncertainty term in the likelihood driven by fits to alternative models. The overall contribution of the $E_{\mathrm{rmv}}$ systematic uncertainty to the total variance on $\Delta m^2_{32}$ using the 2020 (2018) T2K implementation was estimated to be $\sigma_{E_{\text{rmv}}}^2/\sigma_{\Delta m^2}^2=1(6)\%$

Search for R-Parity Violating Decays of Scalar Fermions at LEP

A search for pair-produced scalar fermions under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about 610 pb-1 collected at centre-of-mass energies of sqrt(s) 189-209 GeV. An important consequence of R-parity violation is that the lightest supersymmetric particle is expected to be unstable. Searches of R-parity violating decays of charged sleptons, sneutrinos and squarks have been performed under the assumptions that the lightest supersymmetric particle decays promptly and that only one of the R-parity violating couplings is dominant for each of the decay modes considered. Such processes would yield final states consisting of leptons, jets, or both with or without missing energy. No significant single-like excess of events has been observed with respect to the Standard Model expectations. Limits on the production cross- section of scalar fermions in R-parity violating scenarios are obtained. Constraints on the supersymmetric particle masses are also presented in an R-parity violating framework analogous to the Constrained Minimal Supersymmetric Standard Model.Comment: 51 pages, 24 figures, Submitted to Eur. Phys. J.

Search for the Standard Model Higgs Boson with the OPAL Detector at LEP

This paper summarises the search for the Standard Model Higgs boson in e+e- collisions at centre-of-mass energies up to 209 GeV performed by the OPAL Collaboration at LEP. The consistency of the data with the background hypothesis and various Higgs boson mass hypotheses is examined. No indication of a signal is found in the data and a lower bound of 112.7GeV/C^2 is obtained on the mass of the Standard Model Higgs boson at the 95% CL.Comment: 51 pages, 21 figure

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

The Critically Endangered western chimpanzee declines by 80%

African large mammals are under extreme pressure from unsustainable hunting and habitat loss. Certain traits make large mammals particularly vulnerable. These include late age at first reproduction, long inter-birth intervals, and low population density. Great apes are a prime example of such vulnerability, exhibiting all of these traits. Here we assess the rate of population change for the western chimpanzee, Pan troglodytes verus, over a 24-year period. As a proxy for change in abundance, we used transect nest count data from 20 different sites archived in the IUCN SSC A.P.E.S. database, representing 25,000 of the estimated remaining 35,000 western chimpanzees. For each of the 20 sites, datasets for 2 different years were available. We estimated site-specific and global population change using Generalized Linear Models. At 12 of these sites, we detected a significant negative trend. The estimated change in the subspecies abundance, as approximated by nest encounter rate, yielded a 6% annual decline and a total decline of 80.2% over the study period from 1990 to 2014. This also resulted in a reduced geographic range of 20% (657,600 vs. 524,100&thinsp;km2). Poverty, civil conflict, disease pandemics, agriculture, extractive industries, infrastructure development, and lack of law enforcement, are some of the many reasons for the magnitude of threat. Our status update triggered the uplisting of the western chimpanzee to &ldquo;Critically Endangered&rdquo; on the IUCN Red List. In 2017, IUCN will start updating the 2003 Action Plan for western chimpanzees and will provide a consensus blueprint for what is needed to save this subspecies. We make a plea for greater commitment to conservation in West Africa across sectors. Needed especially is more robust engagement by national governments, integration of conservation priorities into the private sector and development planning across the region and sustained financial support from donors.Additional co-authors: Emma Normand, Kathryn Shutt-Phillips, Alexander Tickle, Elleni Vendras, Adam Welsh, Erin G. Wessling, Christophe Boesc

A measurement of the Tau to Muon branching ratio

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A measurement of the branching ratio of the decay [tau] lepton to five charged hadrons

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