1,887 research outputs found
Tachyon Vacuum in Cubic Superstring Field Theory
In this paper we give an exact analytic solution for tachyon condensation in
the modified (picture 0) cubic superstring field theory. We prove the absence
of cohomology and, crucially, reproduce the correct value for the D-brane
tension. The solution is surprising for two reasons: First, the existence of a
tachyon vacuum in this theory has not been definitively established in the
level expansion. Second, the solution {\it vanishes} in the GSO sector,
implying a ``tachyon vacuum'' solution exists even for a {\it BPS} D-brane.Comment: 16 pages, 2 figure
Bubbling AdS and Vacuum String Field Theory
We show that a family of 1/2--BPS states of SYM is in correspondence
with a family of classical solutions of VSFT with a --field playing the role
of the inverse Planck constant. We show this correspondence by relating the
Wigner distributions of the fermion systems representing such states, to
low energy space profiles of systems of VSFT D-branes. In this context the
Pauli exclusion principle appears as a consequence of the VSFT projector
equation. The family of 1/2--BPS states maps through coarse--graining to
droplet LLM supergravity solutions. We discuss the possible meaning of the
corresponding coarse graining in the VSFT side.Comment: 23 pages, subsection 4.1 added, Appendix suppressed. to be published
in NP
Tachyon Kink on non-BPS Dp-brane in the General Background
This paper is devoted to the study of the tachyon kink on the worldvolume of
a non-BPS Dp-brane that is embedded in general background, including NS-NS two
form B and also general Ramond-Ramond field. We will explicitly show that the
dynamics of the kink is described by the equations of motion that arrise from
the DBI and WZ action for D(p-1)-brane.Comment: 28 page
String Field Theory Vertices for Fermions of Integral Weight
We construct Witten-type string field theory vertices for a fermionic first
order system with conformal weights (0,1) in the operator formulation using
delta-function overlap conditions as well as the Neumann function method. The
identity, the reflector and the interaction vertex are treated in detail paying
attention to the zero mode conditions and the U(1) charge anomaly. The Neumann
coefficients for the interaction vertex are shown to be intimately connected
with the coefficients for bosons allowing a simple proof that the
reparametrization anomaly of the fermionic first order system cancels the
contribution of two real bosons. This agrees with their contribution c=-2 to
the central charge. The overlap equations for the interaction vertex are shown
to hold. Our results have applications in N=2 string field theory, Berkovits'
hybrid formalism for superstring field theory, the \eta\xi-system and the
twisted bc-system used in bosonic vacuum string field theory.Comment: 1+28 pages, minor improvements, references adde
Open Cavity Solutions to the rf in Magnetic Field Problem
It has been observed \cite{break} that breakdown in an 805 MHz pill-box cavi
ty occurs at much lower gradients as an external axial magnetic field is inc
reased. This effect was not observed with on open iris cavity. It is propose d
that this effect depends on the relative angles of the magnetic and maximu m
electric fields: parallel in the pill-box case; at an angle in the open ir is
case. If so, using an open iris structure with solenoid coils in the iris es
should perform even better. A lattice, using this principle, is presented, for
use in 6D cooling for a Muon Collider. Experimental layouts to test th is
principle are proposed.Comment: 3 pages, 7 figures color; submitted to NUFAC0
Accelerator system for the PRISM based muon to electron conversion experiment
The next generation of lepton flavor violation experiments need high
intensity and high quality muon beams. Production of such beams requires
sending a short, high intensity proton pulse to the pion production target,
capturing pions and collecting the resulting muons in the large acceptance
transport system. The substantial increase of beam quality can be obtained by
applying the RF phase rotation on the muon beam in the dedicated FFAG ring,
which was proposed for the PRISM project.This allows to reduce the momentum
spread of the beam and to purify from the unwanted components like pions or
secondary protons. A PRISM Task Force is addressing the accelerator and
detector issues that need to be solved in order to realize the PRISM
experiment. The parameters of the required proton beam, the principles of the
PRISM experiment and the baseline FFAG design are introduced. The spectrum of
alternative designs for the PRISM FFAG ring are shown. Progress on ring main
systems like injection and RF are presented. The current status of the study
and its future directions are discussed.Comment: Studies performed within the PRISM Task Force initiativ
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