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.
16019794
A Stringy Solution to the FCNC Problem
The solution to the supersymmetric FCNC problem may not have a simple field theory interpretation. Here I advocate a possibility based on string selection rules. The requirement of non--trivial Yukawa structures restricts the form of the soft terms such that the FCNC problem often does not arise.
16271509
De Sitter vacua from matter superpotentials
Consistent uplifting of AdS vacua in string theory often requires extra light degrees of freedom in addition to those of a (Kahler) modulus. Here we consider the possibility that de Sitter and Minkowski vacua arise due to hidden sector matter interactions. We find that, in this scheme, the hierarchically small supersymmetry breaking scale can be explained by the scale of gaugino condensation and that interesting patterns of the soft terms arise. In particular, a matter-dominated supersymmetry breaking scenario and a version of the mirage mediation scheme appear in the framework of spontaneously broken supergravity.
17840929
Torsion constraints in the Randall-Sundrum scenario
Torsion appears due to fermions coupled to gravity and leads to the strongest particle physics bounds on flat extra dimensions. In this work, I consider torsion constraints in the case of a warped extra dimension with brane and bulk fermions. From current data I obtain a $3\ensuremath{\sigma}$ bound on the TeV-brane mass scale ${\ensuremath{\Lambda}}_{\ensuremath{\pi}}g~2.2 (10) \mathrm{TeV}$ for the anti-de Sitter curvature $k=1(0.01)$ in (reduced) Planck units. If Dirac or light sterile neutrinos reside on the brane, the bound increases to 17 (78) TeV.
42733826
Electric dipole moments in the limit of heavy superpartners.
Supersymmetric loop corrections induce potentially large CP-violating couplings of the Higgs bosons to nucleons and electrons that do not vanish in the limit of heavy superpartners. The Higgs-mediated CP-odd four-fermion operators are enhanced by tan((3)beta and induce electric dipole moments of heavy atoms which exceed the current experimental bounds for the electroweak scale Higgs masses and tan(beta greater, similar 10. If only the first two sfermion generations are heavy, the Higgs-mediated contributions typically dominate over the Barr-Zee type two-loop diagrams at tan(beta>30.
119248157
Vector Higgs-portal dark matter and the invisible Higgs
The Higgs sector of the Standard Model offers a unique probe of the hidden sector. In this work, we explore the possibility of renormalizable Higgs couplings to the hidden sector vector fields which can constitute dark matter (DM). Abelian gauge sectors with minimal field content, necessary to render the gauge fields massive, have a natural Z2 parity. This symmetry ensures stability of the vector fields making them viable dark matter candidates, while evading the usual electroweak
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.
182123800
Characteristics of Transversal Coherent Beam Instability on the Plateau of 386-Oe Magnetic Field at the SERPUKHOV Accelerator. (Talk, in Russian)
126255062
EXPERIMENTAL STUDY OF COHERENT TRANSVERSE BEAM INSTABILITY AT THE IHEP ACCELERATOR
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
123386574
Experimental investigation of stochastic slow extraction from the U-70 synchrotron
The feasibility of developing a system for stochastic (noise) slow extraction from the U-70 proton synchrotron of the Institute for High Energy Physics is substantiated, and the results from its experimental testing are presented. The existing auxiliary 200-MHz RF system (accelerating frequency, 5.5–6 MHz) is used as a longitudinal kicker. This system is driven by the superposition of a deterministic (nonrandom) RF carrier and additive phase noise. The noise gives rise to longitudinal beam diffusion that forces protons into the third-order transverse extraction resonance. The technical constraints inherent in the U-70 machine are taken into account in the proposed scheme. The extraction technique is expected to provide flat-topped spills having a duration of a few seconds and a low contamination with ripple.