Detecting Gluino-Containing Hadrons

When SUSY breaking produces only dimension-2 operators, gluino and photino masses are of order 1 GeV or less. The gluon-gluino bound state has mass 1.3-2.2 GeV and lifetime > 10^{-5} - 10^{-10} s. This range of mass and lifetime is largely unconstrained because missing energy and beam dump techniques are ineffective. With only small modifications, upcoming K^0 decay experiments can study most of the interesting range. The lightest gluino-containing baryon (uds-gluino) is long-lived or stable; experiments to find it and the uud-gluino are also discussed.Comment: 13 pp, 1 figure (uuencoded). Descendant of hep-ph/9504295, hep-ph/9508291, and hep-ph/9508292, focused on experimental search techniques. To be published in Phys Rev Let

Damage and repair classification in reinforced concrete beams using frequency domain data

This research aims at developing a new vibration-based damage classification technique that can efficiently be applied to a real-time large data. Statistical pattern recognition paradigm is relevant to perform a reliable site-location damage diagnosis system. By adopting such paradigm, the finite element and other inverse models with their intensive computations, corrections and inherent inaccuracies can be avoided. In this research, a two-stage combination between principal component analysis and Karhunen-Loéve transformation (also known as canonical correlation analysis) was proposed as a statistical-based damage classification technique. Vibration measurements from frequency domain were tested as possible damage-sensitive features. The performance of the proposed system was tested and verified on real vibration measurements collected from five laboratory-scale reinforced concrete beams modelled with various ranges of defects. The results of the system helped in distinguishing between normal and damaged patterns in structural vibration data. Most importantly, the system further dissected reasonably each main damage group into subgroups according to their severity of damage. Its efficiency was conclusively proved on data from both frequency response functions and response-only functions. The outcomes of this two-stage system showed a realistic detection and classification and outperform results from the principal component analysis-only. The success of this classification model is substantially tenable because the observed clusters come from well-controlled and known state conditions

LIGHT PHOTINOS AS DARK MATTER

There are good reasons to consider models of low-energy supersymmetry with very light photinos and gluinos. In a wide class of models the lightest $R$-odd, color-singlet state containing a gluino, the $\r0$, has a mass in the 1-2 GeV range and the slightly lighter photino, \pho, would survive as the relic $R$-odd species. For the light photino masses considered here, previous calculations resulted in an unacceptable photino relic abundance. But we point out that processes other than photino self-annihilation determine the relic abundance when the photino and $R^0$ are close in mass. Including \r0\longleftrightarrow\pho processes, we find that the photino relic abundance is most sensitive to the $\r0$-to-\pho mass ratio, and within model uncertainties, a critical density in photinos may be obtained for an $\r0$-to-\pho mass ratio in the range 1.2 to 2.2. We propose photinos in the mass range of 500 MeV to 1.6 GeV as a dark matter candidate, and discuss a strategy to test the hypothesis.Comment: uuencoded compressed tar file containing 32 page LaTeX file and eight postscript figure

Experiments to Find or Exclude a Long-Lived, Light Gluino

Gluinos in the mass range ~1 1/2 - 3 1/2 GeV are absolutely excluded. Lighter gluinos are allowed, except for certain ranges of lifetime. Only small parts of the mass-lifetime parameter space are excluded for larger masses unless the lifetime is shorter than ~ 2 10^{-11} (m_{gluino}/ GeV) sec. Refined mass and lifetime estimates for R-hadrons are given, present direct and indirect experimental constraints are reviewed, and experiments to find or definitively exclude these possibilities are suggested.Comment: 27 pp, latex with 1 uufiled figure, RU-94-35. New version amplifies discussion of some points and corresponds to version for Phys. Rev.

R-parity violation in (t+tˉ)g~(t+\bar t)\tilde g production at LHC and Tevatron

We study the production of $(t+\bar{t}) \tilde{g}$ at the hadron colliders in an R-parity ($R_{p}$) violating supersymmetric model. This process provides us with information not only about $R_{p}$ violation, but may also help us in detecting the supersymmetry itself. It is possible to detect an $R_{p}$ violating signal (with single gluino production) at the future hadron colliders, such as Fermilab Tevatron Run II or CERN Large Hadron Collider (LHC), if the parameters in the supersymmetric $\rlap/ R_{p}$ interactions are not too small, e.g. for $m_{\tilde{g}}=1$ TeV, $\lambda^{''}=0.1$, still hundreds of events are produced at LHC with luminosity $30 fb^{-1}$. Even if we could not detect a signal of $\rlap/R_{p}$ in the experiment, we get stringent constraints on the heavy flavour $\rlap/R_{p}$ couplings. In addition to the minimal supersymmetric standard model we have also considered some models with a heavy gluino as the lightest supersymmetric particle.Comment: 12 pages, 8 figure

Stop and Sbottom Searches in Run II of the Fermilab Tevatron

We estimate the Tevatron Run II potential for top and bottom squark searches. We find an impressive reach in several of the possible discovery channels. We also study some new channels which may arise in non-conventional supersymmetry models. In each case we rely on a detailed Monte Carlo simulation of the collider events and the CDF detector performance in Run I.Comment: 30 pages, LaTeX, 10 figure

Reconstructing f(R) model from Holographic DE: Using the observational evidence

We investigate the corresponding relation between $f(R)$ gravity and an interacting holographic dark energy. By obtaining conditions needed for some observational evidence such as, positive acceleration expansion of universe, crossing the phantom divide line and validity of thermodynamics second law in an interacting HDE model and corresponding it with $f(R)$ mode of gravity we find a viable $f(R)$ model which can explain the present universe. We also obtain the explicit evolutionary forms of the corresponding scalar field, potential and scale factor of universe.Comment: 11page. phys. Scr (2012

Ishemia-Reperfusion enhances GAPDH nitration in aging skeletal muscle

Aging and skeletal muscle ischemia/reperfusion (I/R) injury leads to decreased contractile force generation that increases severely with age. Our studies show that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein expression is significantly decreased at 3 and 5 days reperfusion in the young mouse muscle and at 1, 3, 5, and 7 days in the aged muscle. Using PCR, we have shown that GAPDH mRNA levels in young and old muscle increase at 5 days reperfusion compared to control, suggesting that the protein deficit is not transcriptional. Furthermore, while total tyrosine nitration did not increase in the young muscle, GAPDH nitration increased significantly at 1 and 3 days reperfusion. In contrast, total tyrosine nitration in aged muscle increased significantly at 1, 3, and 5 days of reperfusion, with increases in GAPDH nitration at the same time points. We conclude that GAPDH protein levels decrease following I/R, that this is not transcriptionally mediated, that the aged muscle experiences greater oxidative stress, protein modification and GAPDH degradation, possibly contributing to decreased muscle function. We propose that tyrosine nitration enhances GAPDH degradation following I/R and that the persistent decrease of GAPDH in aged muscle is due to the prolonged increase in oxidative modification in this age group

Predictions and recent results in susy on the lattice

In this brief review, I summarize the current theoretical knowledge in supersymmetry on the lattice, with special emphasis on recent results in the framework of N=1 supersymmetric Yang Mills theory, Wess-Zumino model and Yang-Mills theory with extended supersymmetries.Comment: 15 pages. Invited brief review for Modern Physics Letters A. Minor change

Single gluino production in the R-parity lepton number violating MSSM at the LHC

We examine the $R_{p}$-violating signal of single gluino production associated with a charged lepton or neutrino at the large hadron collider (LHC), in the model of R-parity relaxed supersymmetric model. If the parameters in the ${\rlap/R}_p$ supersymmetric interactions are not too small, and the mass of gluino is considered in the range from several GeV (as the Lightest Supersymmetric Particle) to 800 GeV, the cross section of the single gluino production via Drell-Yan processes can be in the order of $10^2 \sim 10^3$ femto barn, and that via gluon fusion in the order of $10^{-1} \sim 10^3$ femto barn. If the gluino decay can be well detected in the CERN LHC, this process provides a prospective way to probe supersymmetry and $R_p$ violation.Comment: LaTex, 22 pages, 5 EPS file