119349560
Constraints on two-Higgs-doublet models at large tan {beta} from W and Z decays
We study constraints on type-II two-Higgs-doublet models at large tan {beta} from CERN LEP and SLD Z-pole data and from lepton universality violation in W decay. We perform a global fit and find that, in the context of Z decay, the LEP-SLD experimental values for lepton universality violation, R{sub b}, and A{sub b} all somewhat disfavor the model. Contributions from the neutral-Higgs sector can be used to constrain the scalar-pseudoscalar Higgs mass splittings. Contributions from the charged-Higgs sector allow us to constrain the charged-Higgs boson mass. For tan {beta}=100 we obtain the 1{sigma} classical (Bayesian) bounds of m{sub H{sup {+-}}}{>=}670 GeV (370 GeV) and 1{>=}m{sub h{sup 0}}/m{sub A{sup 0}}|{sub {alpha}}{sub ={beta}}=m{sub H{sup 0}}/m{sub A{sup 0}}|{sub {alpha}}{sub =0}{>=}0.68 (0.64). The 2{sigma} bounds are weak. Currently, the Fermilab Tevatron experimental limits on lepton universality violation in W decay provide no significant constraint on the Higgs sector. (c) 2000 The American Physical Society.
119408018
Chargino Contributions to Epsilon and Epsilon-Prime
We analyze the chargino contributions to the K-\bar K mixing and epsilon-prime in the mass insertion approximation and derive the corresponding bounds on the mass insertion parameters. We find that the chargino contributions can significantly enlarge the regions of the parameter space where CP violation can be fully supersymmetric. In principle, the observed values of epsilon and epsilon-prime may be entirely due to the chargino -- up-squark loops.
3003989
Universal torsion-induced interaction from large extra dimensions
We consider the Kaluza-Klein (KK) scenario in which only gravity exists in the bulk. Without the assumption of symmetric connection, the presence of brane fermions induces torsion. The result is a universal axial contact interaction that dominates those induced by KK gravitons. This enhancement arises from a large spin density on the brane. Using a global fit to Z-pole observables, we find the 3sigma bound on the scale of quantum gravity to be 28 TeV for n = 2. If Dirac or light sterile neutrinos are present, the data from SN1987A increase the bound to sqrt[n] M(S)>/=210 TeV.
119352335
Constraints on gauged B-3L(tau) and related theories
We consider extensions of the Standard Model with an extra U(1) gauge boson which couples to B-(alpha L_e + beta L_mu + gamma L_tau) with alpha + beta + gamma = 3. We show that the extra gauge boson necessarily mixes with the Z leading to potentially significant corrections to the Z-f-fbar vertex. The constraints on the size of this correction imposed by the Z-pole data from LEP and SLD are derived.
1934772
The CKM phase in heterotic orbifold models
Abstract We consider properties of the CKM phase in the heterotic orbifold models. We find that at the renormalizable level the CKM phase vanishes identically for the prime orbifolds, whereas it can be nonzero for some nonprime orbifolds. In particular, we study in detail the Z 6 -I orbifold which allows for a nontrivial CKM phase and analyze the modular properties of the corresponding Jarlskog invariant. The CKM phase is shown to vanish if the moduli fields are stabilized at Im T i =±1/2.
15991488
Heterotic string backgrounds and CP violation
Abstract In the framework of Z N orbifolds, we discuss effects of heterotic string backgrounds including discrete Wilson lines on the Yukawa matrices and their connection to CP violation.
126255062
EXPERIMENTAL STUDY OF COHERENT TRANSVERSE BEAM INSTABILITY AT THE IHEP ACCELERATOR
126362745
A CAVITY FOR THE SECOND HARMONIC OF ACCELERATING-FIELD FREQUENCY IN THE IHEP SYNCHROTRON
122053065
Coasting Beam in HERA-p Ring
This document is a report on stud ies of production/tr ansport mechanisms resulting in and of cures against a coasting beam halo observed at the HERA proton ring of DESY. Noises in the 208 MHz RF system, drift beyond RF buckets due to energy loss through synchrotron radiation of the highenergy protons and effect of adding the 52 MHz RF voltage are claimed to account for the diverse observations over the halation effect available by now. The work was performed under Attachment #63 to the Agreement between DESY (Hamburg, Germany) and IHEP (Protvino, Russia), re: Coasting Beam in HERA-p Ring, June 2000.
218611448
A STOCHASTIC SLOW EXTRACTION SCHEME FOR U70 SYNCHROTRON
Outcomes of a feasibility study for a low-budget stochastic slow extraction system in the U70 proton synchrotron of IHEP are reported. The existing 200 MHz (spill) RF system is to be employed as a longitudinal kicker. It will be driven by a sum of a non-random RF carrier plus an additive random amplitude-modulated signal — either quadrature or in-phase, or both. A few novel solutions to be implemented in the longitudinal diffusion technique that would force protons into the conventional 3-rd order transverse extraction resonance are foreseen so as to comply with the technical constraints inherent in U70. Getting a-few-seconds-long and high-quality spills is assessed as being viable with the system in question.
115315717
Analysis of the Feedback-Loop Stability in the RF System of the U-70 Synchrotron
We present a systematic approach for investigating the stability of the accelerating system used in the U-70 proton synchrotron (Institute for High-Energy Physics). This system employs tunable ferrite-loaded cavities and is encircled by six feedback loops (both dedicated and spurious) with a cross-talk through a heavy beam loading, high accelerating rate, and the overlapping of the loop passbands. Ensuring the safety margin against self-excitation of the RF system imposes constraints on the limiting intensity of the beam that is accelerated in the synchrotron