120231669
SPONTANEOUS CP-VIOLATION AND STABILITY OF THE HIGGS POTENTIAL IN MSSM
We study the stability properties of the one-loop corrected Higgs potential in MSSM. For the gaugino–higgsino dominated case, the assumptions allowing spontaneous CP-violation lead to the potential which has neither global nor local minima. The incorporation of a scalar SUSY soft-breaking mass can rectify this problem.
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.
118714441
The NMSSM and string theory
Abstract We study the possibility of constructing the NMSSM from the heterotic string. String-derived NMSSMs are much more rare than MSSMs due to the extra requirement that there exist a light singlet which couples to the Higgs pairs. They share the common feature that the singlet self-interactions are typically suppressed, leading to either the “decoupling” or the Peccei–Quinn limit of the NMSSM. In the latter case, the spectrum contains a light pseudoscalar which may be relevant to the MSSM fine-tuning problem. We provide a Z 6 heterotic orbifold example of the NMSSM with approximate Peccei–Quinn symmetry, whose origin lies in the string selection rules combined with our choice of the vacuum configuration.
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.
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.
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.
109125768
A feedback circuit for the stochastic extraction of protons from the U-70 synchrotron: Development and beam tests
Results of research efforts in 2005 that were directed toward developing a system for stochastic (noise) slow extraction of the beam from the U-70 proton synchrotron of the Institute for High Energy Physics are presented. The goal of the study was to develop a full-function prototype of the stochastic slow extraction system and test it on the beam. This prototype, designed for trial operation during machine runs, is capable of producing lengthy flat-topped smooth spills and suppressing their ripple. Approaches to design of the feedback loop that affects the waiting beam stack (which is neither a linear nor time-invariant system) are discussed. A circuit model of the beam being extracted is proposed and analyzed. A dedicated electronic system for beam experiments is described. Results of the beam tests during the U-70 machine run of 2005, which confirm the serviceability of the noise extraction system prototype, are presented.
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.
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
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