1. Searches For Quark And Lepton Compositeness - Lepton Compositeness
rons. Smallness of the lepton mass CITATION: R.M. Barnett et al., Physical Review D54, 1 (1996) -- 2-- and the success of QED prediction for g--2 suggest chirality conservation, i.e., an excited lepton should not couple to both left- and right-handed components of the corresponding lepton. Excited leptons may be classified by SU(2)ThetaU(1) quantum numbers. Typical examples are: 1. Sequential type ; [ R ] ; ` R : R is necessary unless has a Majorana mass. 2. Mirror type [ L ] ; ` L ; 3. Homodoublet type ; Similar classification can be made for excited quarks. Excited fermions can be pair produced via their gauge couplings. The couplings of excited leptons with Z are listed in the following table (for...

2. Quark and Lepton Compositeness, Searches for - Lepton Compositeness
to be unity. In the following, we denote = Sigma LL for (j LL ; j RR ; j LR ) = (Sigma1; 0; 0) ; = Sigma RR for (j LL ; j RR ; j LR ) = (0; Sigma1; 0) ; = Sigma V V for (j LL ; j RR ; j LR ) = (Sigma1; Sigma1; Sigma1) ; = Sigma AA for (j LL ; j RR ; j LR ) = (Sigma1; Sigma1; Upsilon1) ; (2) as typical examples. Such interactions can arise

3. -- 1-- Searches For Quark And Lepton Compositeness - Lepton Compositeness
3.54> ; j LR ) = (Sigma1; 0; 0) ; = Sigma RR for (j LL ; j RR ; j LR ) = (0; Sigma1; 0) ; = Sigma V V for (j LL ; j RR ; j LR ) = (Sigma1; Sigma1; Sigma1) ; = Sigma AA for (j LL ; j RR ; j LR ) = (Sigma1; Sigma1; Upsilon1) ; (2) as typical examples. Such interactions can arise by constituent interchange (when the fermions have common constituents, e.g., for ee ! ee) and/or by exchange of the binding quanta (whenev

4. A Flavor Symmetry Model for Bilarge Leptonic Mixing and the Lepton Masses - Tommy Ohlsson; Gerhart Seidl
We present a model for leptonic mixing and the lepton masses based on avor symmetries and higher-dimensional mass operators. The model predicts bilarge leptonic mixing (i.e., the mixing angles 12 and 23 are large and the mixing angle 13 is small) and an inverted hierarchical neutrino mass spectrum. Furthermore, it approximately yields the experimental hierarchical mass spectrum of the charged leptons. The obtained values for the leptonic mixing parameters and the neutrino mass squared dierences are all in agreement with atmospheric neutrino data, the Mikheyev{Smirnov{Wolfenstein large mixing angle solution of the solar neutrino problem, and consistent with the upper bound...

5. Search for Lepton Flavor Violation
Using the ZEUS detector at the HERA electron-proton collider, we have searched for lepton flavor violation in ep collisions at a center--of--mass energy ( s) of 300 GeV. Events of the type e + p ! ` +X with a final--state lepton of high transverse momentum, ` = or , were sought. No evidence was found for lepton flavor violation in the combined 1993 and 1994 data samples, for which the integrated luminosities were 0.84 pb p collisions and 2.94 pb p collisions. Limits on coupling vs. mass are provided for leptoquarks and R--parity violating squarks.

6. Large Lepton Flavor Mixing and E - Naoyuki Haba
There are experimental indications of large flavor mixing between ¯ and ø . In the unification models, in which the massless sector includes extra particles beyond the standard model, there possibly appear the mixings between quarks (leptons) and the extra particles. When large mixings occur, lepton flavor mixings can be quite different from quark flavor mixings. By taking the string inspired SU(6) Theta SU(2)R model with global flavor symmetries, we obtain the neutrino flavor mixing sin ` 23 ' = sin ` C around the unfication scale. It can be expected that due to large Yukawa couplings of neutrinos, the renormalization effect increases sin 2` 23 naturally up...

7. Lepton Pair Production In Tagged - Emanuele Leonardi
We studied lepton pair production in single-tagged flfl events using the L3 detector at LEP. A measurement of the process cross section is given for 1:4 GeV 2 !Q 2 !7:6 GeV 2 and 60 GeV 2 !Q 2 !140 GeV 2 . The F 2 photon structure function is then extracted at !Q 2 ?= 1:7 GeV 2 . Finally a study of azimuthal correlations is used to gain access to some so far unmeasured photon structure functions. 1. Introduction The study of the e + e Gamma ! e + e Gamma ` + ` Gamma processes, where ` can be any charged lepton, at LEP energies gives direct access to O(ff 4 ) reactions. The tree level Feynman diagrams involved in the process can be classified as multiperipheral, bremsstrahlung, annihilation, and conversion 1 . In this paper we report on...

8. High-Energy High-Luminosity μ+μ- Collider Design - Robert B. Palmer; Richard Fernow; Juan C. Gallardo; Y. Y. Lee; Yagmur Torun; David Neuffer; David Winn
We discuss the design of a high luminosity (10 35 cm \Gamma2 s \Gamma1 ), high energy (2 + 2 TeV) ¯ + ¯ \Gamma collider, starting from the proton accelerator needed to generate the muon beams and proceeding through the muon storage ring. INTRODUCTION Lepton (e + e \Gamma ) colliders have the valuable property of producing simple, single-particle interactions with little background, and this property is essential in the exploration of new particle states. However, extension of e + e \Gamma colliders to multi-TeV energies is severely performanceconstrained by beamstrahlung, and cost-constrained because two full energy linacs are...

9. Lepton Mass Matrix Models - Yuval Grossman,Yosef Nir
this paper we assume that H is completely broken, namely that all lepton fields carry integer H-charges. We discuss the possibility of an unbroken horizontal symmetry in section 9. 3. General Results

10. Semileptonic Lepton-Number/flavour-Violating - A. Ilakovac,B. A. Kniehl
Motivated by the recent investigation of neutrinoless ø-lepton decays by the CLEO collaboration, we perform a systematic analysis of such decays in a possible new-physics scenario with heavy Dirac/Majorana neutrinos, including heavy-neutrino nondecoupling effects, finite quark masses, and quark as well as meson mixings. We find that ø-lepton decays into an electron or muon and a pseudoscalar or vector meson can have branching ratios close to the experimental sensitivity. Numerical estimates show that the predominant decay modes of this kind are ø Gamma ! e Gamma OE, ø Gamma ! e Gamma ae 0 , and ø Gamma ! e Gamma ß 0 , with branching ratios of order 10 Gamma6 . 1 Introduction Recently, the CLEO collaboration has reported their experimental results on 22 neutrinoless decay channels...

11. Cross Section And Lepton Production With Missing - C. Vallee
ric electromagnetic shower (e) or minimum ionizing particle pattern (¯). H1 ¯ candidates must in addition have a significant signal in the muon detector. Lepton isolation is quantified in the pseudo rapidity-azimuth (j; OE) plane by the distance of the lepton from the closest track ( 0:5 radian) and either the distance of the lepton from the closest hadronic jet ( 1 radian, H1) or the calorimetric energy measured in the vicinity of the lepton ( 4 GeV , ZEUS). Once an isolated lepton is identified, a hypothetical transverse neutrino is reconstructed from the calorimetric missing transverse momentum (e-channel) or the transverse momentum imbalance between the ¯ track and...

12. Cross Section And Lepton Production With Missing - C. Vallee
38> track with a calorimetric electromagnetic shower (e) or minimum ionizing particle pattern (). H1 candidates must in addition have a significant signal in the muon detector. Lepton isolation is quantified in the pseudo rapidity-azimuth (j; OE) plane by the distance of the lepton from the closest track ( 0:5 radian) and either the distance of the lepton from the closest hadronic jet ( 1 radian, H1) or the calorimetric energy measured in the vicinity of the lepton ( 4 GeV , ZEUS). Once an isolated lepton is identified, a hypothetical transverse neutrino is reconstructed from the calorimetric missing transverse momentum (e-channel) or the transverse momentum imbalance between the...

13. Search for Lepton Flavour Violating Z - Ansgar Luig
We have searched for the lepton flavour violating decays Z ! e, Z ! e , Z ! using all OPAL data taken from 1990 to 1993. The data sample corresponds to an integrated luminosity of about 60 pb Gamma1 . We found no candidates in the e channel, and the observed events in the e and channel are consistent with background coming from Z ! and Z ! decays. Our upper limits at 95% C.L. on the branching ratios for lepton flavour violating Z 0 -decays are: Br(Z 0 ! e) 3:0 Theta 10 Gamma6 Br(Z 0 ! e) 2:6 Theta 10 Gamma5 Br(Z 0 ! ) 5:5 Theta 10 Gamma5 : 1 Introdution The experimental non-observation of right-handed neutrinos and the assumption...

14. Lepton Flavour Violation Experiments - Some Recent Developments - Klaus P. Jungmann
. Dedicated experiments searching for lepton flavour violation can be performed very sensitively using K-decays and ¯-decays as well as neutrinoless double fi-decay and muonium to antimuonium conversion. Although there is no confirmed signal reported yet, stringent limits for parameters in speculative extensions to the standard model can be set. Some models could recently be ruled out. I INTRODUCTION All confirmed experimental data acquired to date indicate the conservation of lepton numbers. This fact can be described by several different empirical laws [1--5], some of which follow additive and some obey multiplicative, parity-like, schemes. Experiments have given no indication yet for favouring any of them. The standard model states for...

15. Baryon and Lepton Number Assignment in - Emmanuel A. Paschos,Utpal Sarkar
In E 6 models there are new particles whose baryon number is not uniquely assigned. We point out that the baryon and lepton number assignment to these particles can change the baryogenesis scenario significantly. We consider left-right symmetric extension of the standard model in which (B Gamma L) quantum number is gauged. The identification of (B Gamma L) with a generator of E 6 is used to define the baryon and lepton numbers for the exotic particles in a way that the electroweak baryon and lepton number anomaly corresponding to the SU(2) L group vanishes, i.e., there is no non-perturbative baryon or lepton number violation during the electroweak phase...

16. Measurement of the Tau Lepton Lifetime - R. Balest
We measure the lepton lifetime with + Gamma pairs in which one or both of the 's decays to three charged particles. The data were collected with the CLEO II detector operating at the electron-positron collider CESR at energies on and near the Upsilon(4S ). We use displacements of the three-track vertices to determine the lifetime. The result is = 289:0 Sigma 2:8 Sigma 4:0 fs. Permanent address: BINP, RU-630090 Novosibirsk, Russia 2 I. INTRODUCTION The decay of the lepton provides a useful testing ground for the Standard Model of electroweak interactions [1]. Within the framework of this model the is a sequential lepton, and therefore its properties such as mass, lifetime, and...

17. Test Of Structure Functions Using Lepton Pairs: - W. K. Sakumoto
Introduction In hadron-hadron collisions, massive lepton pairs are produced via the Drell-Yan 1 process. At the Tevatron collider, the hadron-hadron collisions are symmetric p¯p collisions at p s = 1:8 TeV. In the standard model, quarks and anti-quarks annihilate into W or fl =Z bosons, which then decay into lepton pairs: q + ¯ q 0 ! W ! l + (1) ! fl =Z ! l + + l Gamma : Since the p and ¯ p provide the flux of colliding quarks, the Drell-Yan process provides information on the proton's parton distribution functions (PDFs). The leading order quantum chromodynamics (LO QCD) cross section is d 2 oe dM 2 dy

18. Decay Lepton Distribution in Hadronic Collisions - E. Mirkes,C. S. Kim
We propose the measurement of the decay angular distribution of leptons from J=/'s produced at high transverse momentum balanced by a photon [or gluon] in hadronic collisions. The polar and azimuthal angular distribution are calculated in the color singlet model (CSM). It is shown that the general structure of the decay lepton distribution is controlled by four invariant structure functions, which are functions of the transverse momentum and the rapidity of the J=/. We found that two of these structure functions [the longitudinal and transverse interference structure functions] are identical in the CSM. We present analytical and numerical results in the Collins-Soper and in the Gottfried-Jackson frame. 1 The measurement of...

19. Measurement of the Lifetime of the Tau Lepton
The tau lepton lifetime is measured with the L3 detector at LEP using the complete data taken at centre-of-mass energies around the Z pole resulting in # # = 293.2 2.0 (stat) 1.5 (syst) fs. The comparison of this result with the muon lifetime supports lepton universality of the weak charged current at the level of six per mille. Assuming lepton universality, the value of the strong coupling constant, # s is found to be # s (m 2 # ) = 0.319 0.015 (exp) 0.014 (theory). Submitted to Phys. Lett. B 1 Introduction In the Standard Electroweak Model [1], the couplings of the leptonic charged and neutral currents to the gauge bosons are independent...

20. Measurements from Neutrino and Charged Lepton Scattering - Michael H. Shaevitz
Introduction Lepton scattering experiments provide complementary measurements to the high precision measurements performed at LEP/SLC and the Tevatron collider. Neutrino-nucleon and neutrinoelectron scattering depend on the couplings of the Z Gammaboson to the and quarks. The parameters of the Standard Model are now well known, and the couplings measured in neutrino scattering are predicted to high accuracy. Any significant deviation between measurement and prediction would be a possible indication of new physics. The neutrino measurements are complementary to others by measuring different combinations of couplings, in particular couplings to light quarks; by measuring cross sections at moderate space-like momentum transfer compared to the large timelike region explored at colliders; and by extracting cross sections with different radiative correction and...

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