Papers by Belli Krishna Prasad
Physical Review C, 2010
High-statistics measurements of differential cross sections and recoil polarizations for the reac... more High-statistics measurements of differential cross sections and recoil polarizations for the reaction $\gamma p \rightarrow K^+ \Sigma^0$ have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ($\sqrt{s}$) from 1.69 to 2.84 GeV, with an extensive coverage in the $K^+$ production angle. Independent measurements were made using the $K^{+}p\pi^{-}$($\gamma$) and $K^{+}p$($\pi^-, \gamma$) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in $\sqrt{s}$ coverage. Above $\sqrt{s} \approx 2.5$ GeV, $t$- and $u$-channel Regge scaling behavior can be seen at forward- and backward-angles, respectively. Our recoil polarization ($P_\Sigma$) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles we find that $P_\Sigma$ is of the same magnitude but opposite sign as $P_\Lambda$, in agreement with the static SU(6) quark model prediction of $P_\Sigma \approx -P_\Lambda$. This expectation is violated in some mid- and backward-angle kinematic regimes, where $P_\Sigma$ and $P_\Lambda$ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial wave analyses being performed to search for missing baryon resonances.
Physical Review C, 2009
Beam-recoil transferred polarizations for the exclusive e→p→e'K+Λ→,Σ→0 reactions have been measur... more Beam-recoil transferred polarizations for the exclusive e→p→e'K+Λ→,Σ→0 reactions have been measured using the Continuous Electron Beam Accelerator Facility's large acceptance spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. New measurements have been completed at beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer Q2 from 0.7 to 5.4 GeV2, invariant energy W from 1.6 to 2.6 GeV, and the full center-of-mass angular range of the K+ meson. These new data add to the existing CLAS K+Λ measurements at 2.567 GeV, and provide the first-ever data for the K+Σ0 channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to s-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semiclassical partonic models are made to probe the underlying reaction mechanism and the s smacr quark-pair creation dynamics.
Physical Review C, 2010
High-statistics measurements of differential cross sections and recoil polarizations for the reac... more High-statistics measurements of differential cross sections and recoil polarizations for the reaction γp → K + Σ 0 have been obtained using the CLAS detector at Jefferson Lab. We cover center-ofmass energies ( √ s) from 1.69 to 2.84 GeV, with an extensive coverage in the K + production angle. Independent measurements were made using the K + pπ − (γ) and K + p(π − , γ) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR and LEPS results, while offering better statistical precision and a 300-MeV increase in √ s coverage. Above √ s ≈ 2.5 GeV, t-and u-channel Regge scaling behavior can be seen at forward-and backward-angles, respectively. Our recoil polarization (PΣ) measurements represent a substantial increase in kinematic coverage and enhanced precision over previous world data. At forward angles, we find that PΣ is of the same order of magnitude but opposite sign as PΛ, in agreement with the static SU (6) quark model prediction of PΣ ≈ −PΛ. This expectation is violated in some mid-and backward-angle kinematic regimes, where PΣ and PΛ are of similar magnitudes but also have the same signs. In conjunction with several other meson photoproduction results recently published by CLAS, the present data will help constrain the partial-wave analyses being performed to search for missing baryon resonances.
Physical Review C, 2009
High-statistics differential cross sections and spin density matrix elements for the reaction γp ... more High-statistics differential cross sections and spin density matrix elements for the reaction γp → pω have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos θ ω c.m. bins of width 0.1. These are the most precise and extensive ω photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.
Physics Letters B, 2009
We report on the first measurement of the differential cross section of $\phi$-meson photoproduct... more We report on the first measurement of the differential cross section of $\phi$-meson photoproduction for the $d(\gamma,pK^{+}K^{-})n$ exclusive reaction channel. The experiment was performed using a \textcolor{black}{tagged-photon} beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. A combined analysis using data from the $d(\gamma,pK^{+}K^{-})n$ channel and those from a previous publication on coherent $\phi$ production on the deuteron has been carried out to extract the $\phi-N$ total cross section, $\sigma_{\phi N}$. The extracted $\phi-N$ total cross section favors a value above 20 mb. This value is larger than the value extracted using vector-meson dominance models for $\phi$ photoproduction on the proton.
Physical Review C, 2009
High-statistics differential cross sections and spin density matrix elements for the reaction γp ... more High-statistics differential cross sections and spin density matrix elements for the reaction γp → pω have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos θ ω c.m. bins of width 0.1. These are the most precise and extensive ω photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.
Exclusive rho^0 electroproduction on the proton at CLAS
... CT 06824 18 Florida State University, Tallahassee, Florida 32306 19 Rice University, Houston,... more ... CT 06824 18 Florida State University, Tallahassee, Florida 32306 19 Rice University, Houston, Texas 77005-1892 20 Edinburgh University, Edinburgh EH9 3JZ, United Kingdom 21 Universidad Te´cnica Federico Santa Mar´ıa, Casilla 110-V, Valpara´ıso, Chile 22 University of ...
Physical Review C, 2009
High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p e... more High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.
15th Congress of the International Headache Society 23-26 June 2011, Berlin, Germany
Cephalalgia, 2011
To assess bone regeneration in critical sized defects in the rabbit calvarium, filled with the bo... more To assess bone regeneration in critical sized defects in the rabbit calvarium, filled with the bone substitute calcium phosphate cement. Circular bone defects (8mm) were made in both parietal bones of 10 rabbits. One of the defects was filled with the calcium phosphate cement, and the other received autogenous bone harvested from the calvaria. The animals were killed at 3 or 6 weeks (n=5). Data analysis included qualitative assessment of the calvarial specimens and histomorphometric analysis was used to quantify the amount of new bone within the defects. The microscopic analysis of the samples showed bone healing with both calcium phosphate cement and autogenous bone graft. Data obtained from the histomorphometric analysis were statistically analyzed using 2-way analysis of variance and the Tukey's test. Data analysis showed that the autogenous bone graft had significantly more new bone compared with calcium phosphate cement at 3 and 6 weeks. Calcium phosphate cement at 6 weeks presented similar results to autogenous bone at 3 weeks. Both treatments presented an increase in bone healing with time. Treatments allowed bone regeneration that increased with time, however surgical cavities treated with the autogenous graft had more bone formation than those with calcium phosphate cement.
It is a great privilege for us to express our deep sense of gratitude to our Guide Professor S C ... more It is a great privilege for us to express our deep sense of gratitude to our Guide Professor S C Mohanty, Department of Mechanical Engineering, NIT Rourkela for introducing the present topic and to provide us stimulating guidance, constructive criticism and valuable suggestion throughout this project. I shall always cherish my association with him for his constant encouragement and freedom to thought and actions that he rendered to me throughout this project.
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Papers by Belli Krishna Prasad