6,322 research outputs found
Renormalisation of the Fayet-Iliopoulos D-term
We consider the renormalisation of the Fayet-Iliopoulos D-term in a
softly-broken Abelian supersymmetric theory. We show that there exists (at
least through three loops) a renormalisation group invariant trajectory for the
coefficient of the D-term, corresponding to the conformal anomaly solution for
the soft masses and couplings.Comment: 11 pages, TeX, Uses Harvmac (big). References added, minor
corrections (including a sign error for the zeta(3) terms), and discussion of
scheme dependence corrected and amplifie
Oxygen chemisorption cryogenic refrigerator
The present invention relates to a chemisorption compressor cryogenic refrigerator which employs oxygen to provide cooling at 60 to 100 K. The invention includes dual vessels containing an oxygen absorbent material, alternately heated and cooled to provide a continuous flow of high pressure oxygen, multiple heat exchangers for precooling the oxygen, a Joule-Thomson expansion valve system for expanding the oxygen to partially liquefy it and a liquid oxygen pressure vessel. The primary novelty is that, while it was believed that once oxygen combined with an element or compound the reaction could not reverse to release gaseous oxygen, in this case oxygen will indeed react in a reversible fashion with certain materials and will do so at temperatures and pressures which make it practical for incorporation into a cryogenic refrigeration system
Ten degree Kelvin hydride refrigerator
A compact hydride absorption refrigeration system with few moving parts for 10 Kelvin operation is disclosed and comprises liquid hydrogen producing means in combination with means for solidifying and subliming the liquid hydrogen produced. The liquid hydrogen is sublimed at about 10 Kelvin. By using a symmetrical all hydrogen redundant loop system, a 10 Kelvin refrigeration system can be operated for many years with only a fraction of the power required for prior art systems
Two-loop beta-functions and their effects for the R-parity Violating MSSM
We present the full two-loop beta-functions for the MSSM including R-parity
violating couplings. We analyse the effect of two-loop running on the bounds on
R-parity violating couplings, on the nature of the LSP and on the stop masses.Comment: 12 pages, including 2 figures. Plain TeX. Uses Harvmac and epsf.
Revised version with corrected Table and Figure
Snowmass Benchmark Points and Three-Loop Running
We present the full three-loop beta-functions for the MSSM generalised to
include additional matter multiplets in 5, 10 representations of SU(5). We
analyse in detail the effect of three-loop running on the sparticle spectrum
for the MSSM Snowmass Benchmark Points. We also consider the effect on these
spectra of additional matter multiplets (the semi-perturbative unification
scenario).Comment: 28 pages, TeX, 4 figures, 10 tables. Uses Harvmac and eps
Three-stage sorption type cryogenic refrigeration systems and methods employing heat regeneration
A three-stage sorption type cryogenic refrigeration system, each stage containing a fluid having a respectively different boiling point, is presented. Each stage includes a compressor in which a respective fluid is heated to be placed in a high pressure gaseous state. The compressor for that fluid which is heated to the highest temperature is enclosed by the other two compressors to permit heat to be transferred from the inner compressor to the surrounding compressors. The system may include two sets of compressors, each having the structure described above, with the interior compressors of the two sets coupled together to permit selective heat transfer therebetween, resulting in more efficient utilization of input power
Three loop soft running, benchmark points and semi-perturbative unification
We consider three-loop -function corrections to the sparticle spectrum
in the MSSM, with particular emphasis on Snowmass Benchmark points. The three
loop running has little effect on the weakly interacting particle spectrum, but
for the squark masses the effect can be comparable to, or greater than, that of
two loop running. We extend the analysis to the semi-perturbative unification
scenario, where the impact of the three loop corrections becomes even more
dramatic.Comment: 12 pages, TeX, Uses Harvmac (big) and epsf. Added references (v2).
More emphasis on magnitude of three loop corrections (v3
Ultra-violet Finiteness in Noncommutative Supersymmetric Theories
We consider the ultra-violet divergence structure of general noncommutative
supersymmetric gauge theories, and seek theories which are all-orders
finite.Comment: 11 pages, Tex, one figure. Uses harvmac (big) and eps
Fayet-Iliopoulos D-terms and anomaly mediated supersymmetry breaking
We show that in a minimal extension of the MSSM by means of an extra U(1)
gauge group, the negative mass-squared problem characteristic of the Anomaly
Mediated Supersymmetry Breaking scenario is naturally solved by means of
Fayet-Iliopoulos D-terms. We derive a set of sum rules for the sparticle masses
which are consequences of the resulting framework.Comment: 11 pages, including 1 figure. Plain TeX. Uses Harvmac and epsf. Final
version to appear in Phys. Lett. B; some minor improvement
The Exact Tachyon Beta-Function for the Wess-Zumino-Witten Model
We derive an exact expression for the tachyon -function for the
Wess-Zumino-Witten model. We check our result up to three loops by calculating
the three-loop tachyon -function for a general non-linear -model
with torsion, and then specialising to the case of the WZW model.Comment: 13pp, uses harvmac (with figures appended as a a standard PostScript
file), LTH 31
- …