Sample records for tauons

  1. Electromagnetic heavy-lepton pair production in relativistic heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Senguel, M.Y. [Atakent Mahallesi, 3. Etap, Halkali-Kuecuekcekmece, Istanbul (Turkey); Gueclue, M.C.; Mercan, Oe.; Karakus, N.G. [istanbul Technical University, Faculty of Science and Letters, Istanbul (Turkey)


    We calculate the cross sections of electromagnetic productions of muon- and tauon-pair productions from the ultra-relativistic heavy ion collisions. Since the Compton wavelengths of muon and tauon are comparable to the radius of the colliding ions, nuclear form factors play important roles for calculating the cross sections. Recent measurement (Abrahamyan et al., Phys Rev Lett 108:112502, 2012) indicates that the neutrons are differently distributed from the protons; therefore this affects the cross section of the heavy-lepton pair production. In order to see the effects of the neutron distributions in the nucleus, we used analytical expression of the Fourier transforms of the Wood-Saxon distribution. Cross section calculations show that the Wood-Saxon distribution function is more sensitive to the parameter R compared to the parameter a. (orig.)

  2. Constraints on CP violating four-fermion interactions

    International Nuclear Information System (INIS)

    He, X.G.; McKellar, B.


    It has been shown that CP violating electron-nucleon and nucleon-nucleon interactions can induce atomic electric dipole moments and are therefore constrained from experimental data. We show that using the experimental upper bounds on neutron and electron electric dipole moments, one can also obtain constraints, in some cases better ones, on these interactions. In addition stringent constraints can also be obtained for muon-quark and tauon-quark four-fermion CP violating interactions, which cannot be constrained from atomic electric dipole moment experiments. 12 refs., 2 tabs., 1 fig

  3. Electromagnetic pair production in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Bottcher, C.; Strayer, M.R.


    We survey the production of electron, muon and tauon pairs in collisions between nuclei at ultra-relativistic energies. Such studies enhance our understanding of the role of the vacuum in field theory, and provide essential input for several experimental programs. A variety of models for the nuclear and nucleon form factors have been considered, revealing some degree of sensitivity to assumptions about sub-nuclear structure. We predict that the cross sections, even at high invariant masses and transverse momenta, are large on hadronic scales, and should act as useful probes of nuclear and nucleon form factors. 21 refs., 5 figs

  4. Lepton dipole moments

    CERN Document Server

    Marciano, William J


    This book provides a self-contained description of the measurements of the magnetic dipole moments of the electron and muon, along with a discussion of the measurements of the fine structure constant, and the theory associated with magnetic and electric dipole moments. Also included are the searches for a permanent electric dipole moment of the electron, muon, neutron and atomic nuclei. The related topic of the transition moment for lepton flavor violating processes, such as neutrinoless muon or tauon decays, and the search for such processes are included as well. The papers, written by many o

  5. On the origin of mass in the standard model

    International Nuclear Information System (INIS)

    Sundman, S.


    A model is proposed in which the presently existing elementary particles are the result of an evolution proceeding from the simplest possible particle state to successively more complex states via a series of symmetry-breaking transitions. The properties of two fossil particles — the tauon and muon — together with the observed photon–baryon number ratio provide information that makes it possible to track the early development of particles. A computer simulation of the evolution reveals details about the purpose and history of all presently known elementary particles. In particular, it is concluded that the heavy Higgs particle that generates the bulk of the mass of the Z and W bosons also comes in a light version, which generates small mass contributions to the charged leptons. The predicted mass of this 'flyweight' Higgs boson is 0.505 MeV/c 2 , 106.086 eV/c 2 or 12.0007 μeV/c 2 (corresponding to a photon of frequency 2.9018 GHz) depending on whether it is associated with the tauon, muon or electron. Support for the conclusion comes from the Brookhaven muon g-2 experiment, which indicates the existence of a Higgs particle lighter than the muon. (author)

  6. Behavioral effects of neurofeedback in adolescents with ADHD: a randomized controlled trial. (United States)

    Bink, Marleen; van Nieuwenhuizen, Chijs; Popma, Arne; Bongers, Ilja L; van Boxtel, Geert J M


    Neurofeedback has been proposed as a potentially effective intervention for reducing Attention Deficit Hyperactivity Disorder (ADHD) symptoms. However, it remains unclear whether neurofeedback is of additional value to treatment as usual (TAU) for adolescents with clinical ADHD symptoms. Using a multicenter parallel-randomized controlled trial design, adolescents with ADHD symptoms were randomized to receive either a combination of TAU and neurofeedback (NFB + TAU, n = 45) or TAU-only (n = 26). Randomization was computer generated and stratified for age group (ages 12 through 16, 16 through 20, 20 through 24). Neurofeedback treatment consisted of approximately 37 sessions of theta/sensorimotor rhythm (SMR)-training on the vertex (Cz). Primary behavioral outcome measures included the ADHD-rating scale, Youth Self Report, and Child Behavior Checklist all assessed pre- and post-intervention. Behavioral problems decreased equally for both groups with medium to large effect sizes, range of partial η2 = 0.08-0.31, p neurofeedback and TAU was as effective as TAU-only for adolescents with ADHD symptoms. Considering the absence of additional behavioral effects in the current study, in combination with the limited knowledge of specific treatment effects, it is questionable whether theta/SMR neurofeedback for adolescents with ADHD and comorbid disorders in clinical practice should be used. Further research is warranted to investigate possible working mechanisms and (long-term) specific treatment effects of neurofeedback.

  7. Lepton flavor violation with displaced vertices

    Directory of Open Access Journals (Sweden)

    Julian Heeck


    Full Text Available If light new physics with lepton-flavor-violating couplings exists, the prime discovery channel might not be ℓ→ℓ′γ but rather ℓ→ℓ′X, where the new boson X could be an axion, majoron, familon or Z′ gauge boson. The most conservative bound then comes from ℓ→ℓ′+inv, but if the on-shell X can decay back into leptons or photons, displaced-vertex searches could give much better limits. We show that only a narrow region in parameter space allows for displaced vertices in muon decays, μ→eX,X→γγ,ee, whereas tauon decays can have much more interesting signatures.

  8. Active zone proteins are transported via distinct mechanisms regulated by Par-1 kinase.

    Directory of Open Access Journals (Sweden)

    Kara R Barber


    Full Text Available Disruption of synapses underlies a plethora of neurodevelopmental and neurodegenerative disease. Presynaptic specialization called the active zone plays a critical role in the communication with postsynaptic neuron. While the role of many proteins at the active zones in synaptic communication is relatively well studied, very little is known about how these proteins are transported to the synapses. For example, are there distinct mechanisms for the transport of active zone components or are they all transported in the same transport vesicle? Is active zone protein transport regulated? In this report we show that overexpression of Par-1/MARK kinase, a protein whose misregulation has been implicated in Autism spectrum disorders (ASDs and neurodegenerative disorders, lead to a specific block in the transport of an active zone protein component- Bruchpilot at Drosophila neuromuscular junctions. Consistent with a block in axonal transport, we find a decrease in number of active zones and reduced neurotransmission in flies overexpressing Par-1 kinase. Interestingly, we find that Par-1 acts independently of Tau-one of the most well studied substrates of Par-1, revealing a presynaptic function for Par-1 that is independent of Tau. Thus, our study strongly suggests that there are distinct mechanisms that transport components of active zones and that they are tightly regulated.

  9. Two Light Sterile Neutrinos that Mix Maximally with Each Other and Moderately with Three Active Neutrinos

    International Nuclear Information System (INIS)

    Krolikowski, W.


    Since the 3+1 neutrino models with one light sterile neutrino turn out to be not very effective, at least two light sterile neutrinos may be needed to reconcile the solar and atmospheric neutrino experiments with the LSND result, if this is confirmed by the ongoing MiniBooNE experiment (and when the CPT invariance is assumed to hold for neutrino oscillations). We present an attractive 3+2 neutrino model, where two light sterile neutrinos mix maximally with each other, in analogy to the observed maximal mixing of muon and tauon active neutrinos. But, while the mixing of ν e and (ν μ - ν τ )/√2 is observed as large (though not maximal), the mixing of ν e with the corresponding combination of two light sterile neutrinos is expected to be only moderate because of the reported smallness of LSND oscillation amplitude. The presented model turns out, however, not to be more effective in explaining the hypothetic LSND result than the simplest 3+1 neutrino model. On the other hand, in the considered 3+2 model, the deviations from conventional oscillations of three active neutrinos appear to be minimal within a larger class of 3+2 models. (author)

  10. Fractional statistics, exceptional preons, scalar dark matter, lepton number violation, neutrino masses, and hidden gauge structure

    International Nuclear Information System (INIS)

    Zee, A.


    A brief review is given of the basics of fractional statistics, which is based on the Dirac-Bohm-Aharanov effect. Some group theoretic aspects of exceptional preons are breifly described, and a theory is proposed containing hypercolor and hyperflavor with G/sub HC/ x G/sub HF/ = E(6) x E(6) and preons in (27,27). It is also suggested that the dark matter in the universe is due to a scalar field which transforms as a singlet under SU(3) x SU(2) x U(1) and interacts only via the Higgs boson. Some speculation is made on the existence and physical consequences of a SU(2) singet charged scalar field which couples to two lepton doublet, necessarily violating electron, muon, and tauon numbers. The Majorana masses of neutrinos are discussed as the result of breaking the total lepton number. Abelian gauge field hidden inside non-abelian gauge theory is briefly described in analogy to the electromagnetic potential term. 20 refs

  11. Extracting limits for the difuse non-electron neutrino flux from SNO data

    Energy Technology Data Exchange (ETDEWEB)

    Miguez, B.S.R.; Kemp, E.; Peres, O.L.G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin


    Full text. There is a prediction of a diffuse neutrino flux yield from the time integration of all supernova already exploded in the past governed by stellar formation and supernovae occurrence rates. The spectral characteristics of these neutrinos differ from those from recent supernovae mainly in two features: the reduction in their fluxes and their energy 'redshift' due the expansion of the universe. Thus, despite the fact that one single supernova is a transient state, their cumulative effect produces a steady flux of diffuse neutrinos everywhere in universe. These neutrinos have never been observed before. Only upper limits on their fluxes have been reported by the collaborations operating neutrino telescopes. Recently the SNO experiment have made an analysis where the total flux of diffuse electron neutrinos has an upper limit of phi{sub e} <= 61-93 cm{sup -2} s{sup -1}, depending on a specific supernova model. At the present, the best limit for the diffuse flux of non-electron neutrinos is phi{sub x} <= 10{sub 4} cm{sup -2} s{sup -1}, resulted from an analysis of the Super-Kamiokande data. In this work we have extended the SNO analysis including the elastic scattering on electrons via neutral current interactions to extract information on diffuse flux of the non-electron neutrino flavours (i.e. muon and tauon neutrinos). We make a comparison among our results and others from different experiments (LVD, SK, LSD). (author)

  12. Search for νμ → νe oscillations

    International Nuclear Information System (INIS)

    Godley, A.R.


    Full text: Neutrino oscillations, the changing of neutrino flavour state from one of τ, μ or e, to another, are proof of massive neutrinos, in turn pointing to Physics beyond the Standard Model, and so are of great current interest. Solar and atmospheric neutrino results suggested evidence for neutrino oscillations. Further, a tau neutrino mass of ∼ 10 eV could supply the missing mass needed to close the Universe. To satisfy the increasing interest, CERN's Neutrino Physics Program commissioned two concurrent experiments to investigate the possibility of neutrino oscillations, one of which is NOMAD, Neutrino Oscillation Magnetic Detector. NOMAD was designed to verify or deny the earlier positive neutrino oscillations results by searching for muon to tauon neutrino oscillations in accelerator neutrinos. The LSND experiment later provided evidence for muon to electron neutrino oscillations, but due to the multi-purpose design of NOMAD, it was also possible to investigate this channel. Moreover, the area of phase space being uncovered, (related to neutrino energy and oscillation length), overlaps considerably with that of LSND. An electron neutrino oscillation search involves looking for electron neutrinos in what is primarily a muon neutrino beam, with just a small contamination of electron neutrinos. It is surmised that the excess of electron neutrinos come from oscillated muon neutrinos. This type of search is called an appearance search. The principles of such a search will be detailed herein. These include a breakdown of the CERN Neutrino Beam and a method for detecting and collating different neutrino flavours at NOMAD

  13. Internet-based attentional bias modification training as add-on to regular treatment in alcohol and cannabis dependent outpatients: a study protocol of a randomized control trial. (United States)

    Heitmann, Janika; van Hemel-Ruiter, Madelon E; Vermeulen, Karin M; Ostafin, Brian D; MacLeod, Colin; Wiers, Reinout W; DeFuentes-Merillas, Laura; Fledderus, Martine; Markus, Wiebren; de Jong, Peter J


    The automatic tendency to attend to and focus on substance-related cues in the environment (attentional bias), has been found to contribute to the persistence of addiction. Attentional bias modification (ABM) interventions might, therefore, contribute to treatment outcome and the reduction of relapse rates. Based on some promising research findings, we designed a study to test the clinical relevance of ABM as an add-on component of regular intervention for alcohol and cannabis patients. The current protocol describes a study which will investigate the effectiveness and cost-effectiveness of a newly developed home-delivered, multi-session, internet-based ABM (iABM) intervention as an add-on to treatment as usual (TAU). TAU consists of cognitive behavioural therapy-based treatment according to the Dutch guidelines for the treatment of addiction. Participants (N = 213) will be outpatients from specialized addiction care institutions diagnosed with alcohol or cannabis dependency who will be randomly assigned to one of three conditions: TAU + iABM; TAU + placebo condition; TAU-only. Primary outcome measures are substance use, craving, and rates of relapse. Changes in attentional bias will be measured to investigate whether changes in primary outcome measures can be attributed to the modification of attentional bias. Indices of cost-effectiveness and secondary physical and psychological complaints (depression, anxiety, and stress) are assessed as secondary outcome measures. This randomized control trial will be the first to investigate whether a home-delivered, multi-session iABM intervention is (cost-) effective in reducing relapse rates in alcohol and cannabis dependency as an add-on to TAU, compared with an active and a waiting list control group. If proven effective, this ABM intervention could be easily implemented as a home-delivered component of current TAU. Netherlands Trial Register, NTR5497 , registered on 18th September 2015.

  14. Neutrino physics-the link between the microcosmos and the macrocosmos, a study in two parts: (1) Theoretical-a look at the tau neutrino mass and other quantum electrodynamical effects in third family lepton interactions and (2) Experimental-underwater astronomy in Hawai'i, the short prototype string of the Deep Underwater Muon and Neutrino Detector project

    International Nuclear Information System (INIS)

    Babson, J.F.


    The nineteen eighties has been a time in which Cosmology and Particle Physics have come together. This dissertation reflects that trend. It does so in two ways. First, in Chapters 1 through 3, there is a theoretical investigation into some aspects of generational universality. The consequences of a third lepton, namely the tauon, and an associated tau neutrino, are explored in terms of phenomenology (mass and V-A consistency) that may shed insight into questions of neutrino mass and increased symmetry at higher energies. Second, in Chapters 4 through 11, there is an experimental investigation in the form of constructing and operating the first stage of the DUMAND (Deep Underwater Muon and Neutrino Detection) project which was a ship suspended muon and neutrino telescope called the SPS (Short Prototype String). This detector is of the water Cherenkov type and is the first time such an instrument has been successfully built and tested for use in the ocean. Chapters 6 through 10 are devoted to the detailed documentation of the parts of the SPS and its technology integration that I designed, prototyped, and debugged. In particular, a complete description is given to the command and control communications system of the string, the digital control electronics and associated software for the Optical, Calibration, and Power modules as well as the fast digitizing electronics or String Bottom Controller (SBC). This includes the development of a microcontroller language UHPS (Underwater Hawai'i Programming System). Finally, Chapter 11 is an analysis of SPS data in terms of ascertaining a purely statistically based downward traveling muon rate at a depth of 4.0 Km yielding (2.06 ± 0.68) x 10 -2 Hz