Scaling Bounded Model Checking By Transforming Programs With Arrays

Bounded Model Checking is one the most successful techniques for finding bugs in program. However, model checkers are resource hungry and are often unable to verify programs with loops iterating over large arrays.We present a transformation that enables bounded model checkers to verify a certain class of array properties. Our technique transforms an array-manipulating (ANSI-C) program to an array-free and loop-free (ANSI-C) program thereby reducing the resource requirements of a model checker significantly. Model checking of the transformed program using an off-the-shelf bounded model checker simulates the loop iterations efficiently. Thus, our transformed program is a sound abstraction of the original program and is also precise in a large number of cases - we formally characterize the class of programs for which it is guaranteed to be precise. We demonstrate the applicability and usefulness of our technique on both industry code as well as academic benchmarks

Efficient Certified RAT Verification

Clausal proofs have become a popular approach to validate the results of SAT solvers. However, validating clausal proofs in the most widely supported format (DRAT) is expensive even in highly optimized implementations. We present a new format, called LRAT, which extends the DRAT format with hints that facilitate a simple and fast validation algorithm. Checking validity of LRAT proofs can be implemented using trusted systems such as the languages supported by theorem provers. We demonstrate this by implementing two certified LRAT checkers, one in Coq and one in ACL2

Analysis of hadronic transitions in Υ(3S) decays

This is the publisher's version, also available electronically from http://journals.aps.org/prd/abstract/10.1103/PhysRevD.49.40.Using the CLEO II detector, we have measured the branching fractions for Υ(3S)→ππΥ(1S), Υ(3S)→ππΥ(2S), and the cascade Υ(3S)→Υ(2S)+X, Υ(2S)→π+π−Υ(1S), analyzing the exclusive mode where the daughter Υ state decays to a e(+)e(−) or μ(+)μ(−) pair, as well as the inclusive π(+)π(−) transitions where the final Υ state decays into hadrons. Properties of the ππ system are analyzed. Searches for the cascade decay Υ(3S)→π+π−h(b), h(b)→γη(b) and Υ(3S)→π0h(b) were also performed

Observation of exclusive B decays to final states containing a charmed baryon

Using data collected in the region of the Upsilon(4S) resonance with the CLEO-II detector, we report on the first observation of exclusive decays of the B meson to final states with a charmed baryon. We have measured the branching fractions B(B- --> Lambda(c)(+)(p) over bar pi(-)) = (0.62(-0.20)(+0.23) +/- 0.11 +/- 0.10) X 10(-3) and B((B) over bar(0) --> Lambda(c)(+)(p) over bar pi(+)pi(-)) = (1.33(-0.42)(+0.46) +/- 0.31 +/- 0.21) X 10(-3), where the first error is statistical, the second is systematic, and the third is due to uncertainty in the Lambda(c)(+) branching fractions. In addition, we report upper limits for final states of the form (B) over bar --> Lambda(c)(+)(p) over bar(n pi) and Lambda(c)(+)(p) over bar(n pi)pi(0), where (n pi) denotes up to four charged pions. [S0031-9007(97)04176-8]

Measurement of the B semileptonic branching fraction with lepton tags

We have used the CLEO II detector and 2.06 fb(-1) of Y(4S) data to measure the B-meson semileptonic branching fraction. The B --> Xe nu momentum spectrum was obtained over nearly the full momentum range by using charge and kinematic correlations in events with a high-momentum lepton tag and an additional electron. We find B(B --> Xe nu) = (10.49 +/- 0.17 +/- 0.43)%, with overall systematic uncertainties less than those of untagged single-lepton measurements. We use this result to calculate the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V-cb and to set an upper limit on the fraction of Y(4S) decays to final states other than B (B) over bar

Limits on flavor changing neutral currents in D-0 meson Decays

Using the CLEO II detector at the Cornell Electron Storage Ring, we have searched for flavor changing neutral currents and lepton family number violations in D-0 meson decays. The upper limits on the branching fractions for D-0 --> l(+)l(-) and D-0 --> X(0)l(+)l(-) are in the range 10(-5) to 10(-4), where X(0) can be a pi(0), K-s(0), eta, rho(0), omega, (K) over bar(*0) or phi meson, and the l(+)l(-) pair can be e(+)e(-), mu(+)mu(-), or e(+/-)mu(-/+). Although these limits are above the theoretical predictions, most are new or an order of magnitude lower than previous limits

Dalitz Plot Analysis of the Decay D^+ --> K^- pi^+ pi^+ and Indication of a Low-Mass Scalar K pi Resonance

We study the Dalitz plot of the decay D^+ --> K^- pi^+ pi^+ with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known K pi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K^*_0(1430) to float, we obtain values consistent with those from PDG but the chi^2 per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797 +/- 19 +/- 43 MeV/c^2 and width 410 +/- 43 +/- 87 MeV/c^2. The mass and width of the K^*_0(1430) become 1459 +/- 7 +/- 5 MeV/c^2 and 175 +/- 12 +/- 12 MeV/c^2, respectively. Our results provide new information on the scalar sector in hadron spectroscopy.Comment: Accepted for publication in Physical Review Letter

Experimental evidence for a light and broad scalar resonance in D+→π−π+π+D^+\to \pi^-\pi^+\pi^+ decay

From a sample of $1172 \pm 61$ $D^+ \to \pi^- \pi^+ \pi^+$ decay, we find $\Gamma (D^+ \to \pi^- \pi^+ \pi^+) / \Gamma (D^+ \to K^- \pi^+ \pi^+) = 0.0311 \pm 0.0018 ^{+0.0016}_{-0.0026}$. Using a coherent amplitude analysis to fit the Dalitz plot of this decays, we find strong evidence that a scalar resonance of mass $478^{+24}_{-23} \pm 17$ MeV/$c^2$ and width $324^{+42}_{-40} \pm 21$ MeV/$c^2$ accounts for approximately half of all decays.Comment: 10 pages, 3 eps figure

Tau decays into three charged leptons and two neutrinos

We search for the radiative leptonic tau decays tau --> ee(+) e(-)nu(tau)nu(e) and tau --> mu e(+)e(-)nu(tau)nu(mu) using 3.60 fb(-1) of data collected by the CLEO-II experiment at the Cornell Electron Storage Ring. We present a first observation of the tau --> ee(+)e(-)nu(tau)nu(e) process. For this channel we measure the branching fraction B(tau --> ee(+)e(-)nu(tau)nu(e)) = (2.7(-1.1-0.4-0.3)(+1.5+0.4+0.1)) X 10(-5). An upper limit is established for the second channel: B(tau --> mu e(+)e(-)nu(tau)nu(mu)) < 3.2 X 10(-5) at 90% C.L. Both results are consistent with the rates expected from standard model predictions