New Results on Heavy Flavor Baryons

2006 ◽  
Vol 21 (27) ◽  
pp. 5482-5487
Author(s):  
James S. Russ
Keyword(s):  
High Sensitivity ◽  
Experimental Results ◽  
High Mass ◽  
Heavy Flavor ◽  
Lattice Gauge ◽  
Charm Baryon ◽  
Charm Baryons ◽  
Double Charm ◽  
Effective Theories ◽  
New Formula

Heavy flavor baryons are attractive systems for testing effective theories for weak lifetime and decay systematics. Recently, new experimental results have mitigated one historic problem in the weak lifetime systematics and continued another. The charm baryon system continues to show new high mass, narrow states well isolated from one another. The spectroscopy of these states will challenge new advances in lattice gauge theoretic calculations of baryon structure. Double charm baryons still are seen only by SELEX, which showed a new [Formula: see text] candidate. High-sensitivity searches by BELLE and BaBar show only featureless background.

scholarly journals Weak decays of bottom-charm baryons: $$\mathcal {B}_{bc}\rightarrow \mathcal {B}_bP$$

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
Jia-Jie Han ◽  
Rui-Xiang Zhang ◽  
Hua-Yu Jiang ◽  
Zhen-Jun Xiao ◽  
Fu-Sheng Yu
Keyword(s):  
Final State Interaction ◽  
Light Quark ◽  
Decay Rates ◽  
Long Distance ◽  
Final State ◽  
Decay Modes ◽  
Weak Decays ◽  
Charm Baryon ◽  
Charm Baryons ◽  
Double Charm

AbstractAfter the discovery of the double-charm baryon $$\Xi _{cc}^{++}$$ Ξ cc + + by LHCb, one of the most important topics is to search for the bottom-charm baryons which contain a b quark, a c quark and a light quark. In this work, we study the two-body non-leptonic weak decays of a bottom-charm baryon into a spin-1/2 bottomed baryon and a light pseudoscalar meson with the short-distance contributions calculated under the factorization hypothesis and the long-distance contributions considering the final-state-interaction effects. The branching fractions of all fifty-seven decay channels are estimated. The results indicate that $$\Xi _{bc}^+\rightarrow \Xi _b^0\pi ^+$$ Ξ bc + → Ξ b 0 π + , $$\Xi _{bc}^{0}\rightarrow \Xi _{b}^{-}\pi ^+$$ Ξ bc 0 → Ξ b - π + and $$\Omega _{bc}^0\rightarrow \Omega _b^-\pi ^+$$ Ω bc 0 → Ω b - π + decay modes have relatively large decay rates and thus could be used to experimentally search for the bottom-charm baryons. The topological diagrams and the SU(3) symmetry of bottom-charm baryon decays are discussed.

scholarly journals GASTON: Galactic Star Formation with NIKA2. Evidence for the mass growth of star-forming clumps

2021 ◽  
Author(s):  
A J Rigby ◽  
N Peretto ◽  
R Adam ◽  
P Ade ◽  
M Anderson ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Galactic Plane ◽  
High Sensitivity ◽  
High Mass ◽  
Evolutionary Stage ◽  
Mass Star ◽  
Mass Growth ◽  
Star Forming ◽  
Compact Source

Abstract Determining the mechanism by which high-mass stars are formed is essential for our understanding of the energy budget and chemical evolution of galaxies. By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we have conducted high-sensitivity and large-scale mapping of a fraction of the Galactic plane in order to search for signatures of the transition between the high- and low-mass star-forming modes. Here, we present the first results from the Galactic Star Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m telescope which is mapping ≈2 deg2 of the inner Galactic plane (GP), centred on ℓ = 23${_{.}^{\circ}}$9, b = 0${_{.}^{\circ}}$05, as well as targets in Taurus and Ophiuchus in 1.15 and 2.00 mm continuum wavebands. In this paper we present the first of the GASTON GP data taken, and present initial science results. We conduct an extraction of structures from the 1.15 mm maps using a dendrogram analysis and, by comparison to the compact source catalogues from Herschel survey data, we identify a population of 321 previously-undetected clumps. Approximately 80 per cent of these new clumps are 70 μm-quiet, and may be considered as starless candidates. We find that this new population of clumps are less massive and cooler, on average, than clumps that have already been identified. Further, by classifying the full sample of clumps based upon their infrared-bright fraction – an indicator of evolutionary stage – we find evidence for clump mass growth, supporting models of clump-fed high-mass star formation.

Specific Detection of Staphylococcus Enterotoxin B in Milk Using Piezoresistive Cantilever Aptasensor

2015 ◽  
Vol 645-646 ◽  
pp. 1298-1302
Author(s):  
Rui Zhao ◽  
Yong Zheng Wen ◽  
Wei Ma ◽  
Jian Cheng Yang ◽  
Xiao Mei Yu
Keyword(s):  
High Sensitivity ◽  
Rapid Response ◽  
Experimental Results ◽  
Quick Response ◽  
Specific Detection ◽  
Detection Range ◽  
Coated Surface ◽  
Enterotoxin B ◽  
Food Commodities ◽  
Staphylococcus Enterotoxin B

In this paper, an aptasensor with high sensitivity and rapid response was developed for the detection of staphylococcus enterotoxin B (SEB) by using thiol-modified piezoresistive cantilever. Thiol-modified aptamers, acting as the functionalized sensing elements, were immobilized on the nanogold-coated surface of the sensing cantilever as agents for detecting SEB. By using the functionalized aptasensors, different concentrations of SEB were detected with a wide detection range of 6-100 ng/mL and a quick response in milk. The experimental results indicated that the cantilever-based aptasensors had sufficient sensitivity for the detection of SEB in real food commodities and might provide an economical platform for on-site detections of different toxicants with the advantages of portability, high sensitivity, and rapid response.

scholarly journals PHENIX heavy flavor highlights

2020 ◽  
pp. 2040006
Author(s):  
Takashi Hachiya
Keyword(s):  
Perturbative Qcd ◽  
Semileptonic Decay ◽  
Large Mass ◽  
High Energy ◽  
Gluon Density ◽  
Experimental Results ◽  
Heavy Flavor ◽  
Phenix Experiment ◽  
Heavy Flavor Production

Heavy flavor production is a sensitive probe of the initial gluon density in the nucleon and is modified by the entire evolution of the hot quark and gluon medium created in high-energy nucleus–nucleus collisions. Besides, it is a process that can be calculated by perturbative QCD because of their large mass. The PHENIX experiment at RHIC studied the heavy flavor productions for a broad momentum and rapidity ranges using single leptons from the semileptonic decay of charm and bottom hadrons, and dileptons from [Formula: see text] decays in [Formula: see text], [Formula: see text]A, and Au [Formula: see text] Au collisions at [Formula: see text][Formula: see text]200[Formula: see text]GeV. In these proceedings, the recent experimental results in [Formula: see text], Au [Formula: see text] Au, and the small collision systems are presented and the heavy flavor productions and their modifications are discussed.

Experimental and numerical evaluation of a genetically engineered M13 bacteriophage with high sensitivity and selectivity for 2,4,6-trinitrotoluene

2019 ◽  
Vol 17 (23) ◽  
pp. 5666-5670 ◽  
Author(s):  
Won-Geun Kim ◽  
Chris Zueger ◽  
Chuntae Kim ◽  
Winnie Wong ◽  
Vasanthan Devaraj ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Numerical Evaluation ◽  
High Sensitivity ◽  
Genetically Engineered ◽  
Experimental Results ◽  
Sensor System ◽  
M13 Bacteriophage ◽  
Sensitivity And Selectivity

This study includes the experimental results of a sensitive M13 bacteriophage-based sensor system that are well matched with the quantum mechanics calculation.

Design and Testing of a Can Combustor for a Small Gas Turbine Application

2013 ◽  
Author(s):  
K. V. L. Narayana Rao ◽  
N. Ravi Kumar ◽  
G. Ramesha ◽  
M. Devathathan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Pressure Loss ◽  
High Energy ◽  
Experimental Results ◽  
High Mass ◽  
Test Facility ◽  
Design Requirements

Can type combustors are robust, with ease of design, manufacturing and testing. They are extensively used in industrial gas turbines and aero engines. This paper is mainly based on the work carried out in designing and testing a can type combustion chamber which is operated using JET-A1 fuel. Based on the design requirements, the combustor is designed, fabricated and tested. The experimental results are analysed and compared with the design requirements. The basic dimensions of the combustor, like casing diameter, liner diameter, liner length and liner hole distribution are estimated through a proprietary developed code. An axial flow air swirler with 8 vanes and vane angle of 45 degree is designed to create a re-circulation zone for stabilizing the flame. The Monarch 4.0 GPH fuel nozzle with a cone angle of 80 degree is used. The igniter used is a high energy igniter with ignition energy of 2J and 60 sparks per minute. The combustor is modelled, meshed and analysed using the commercially available ansys-cfx code. The geometry of the combustor is modified iteratively based on the CFD results to meet the design requirements such as pressure loss and pattern factor. The combustor is fabricated using Ni-75 sheet of 1 mm thickness. A small combustor test facility is established. The combustor rig is tested for 50 Hours. The experimental results showed a blow-out phenomenon while the mass flow rate through the combustor is increased beyond a limit. Further through CFD analysis one of the cause for early blow out is identified to be a high mass flow rate through the swirler. The swirler area is partially blocked and many configurations are analysed. The optimum configuration is selected based on the flame position in the primary zone. The change in swirler area is implemented in the test model and further testing is carried out. The experimental results showed that the blow-out limit of the combustor is increased to a good extent. Hence the effect of swirler flow rate on recirculation zone length and flame blow out is also studied and presented. The experimental results showed that the pressure loss and pattern factor are in agreement with the design requirements.

scholarly journals Low levels of methanol deuteration in the high-mass star-forming region NGC 6334I

2018 ◽  
Vol 615 ◽  
pp. A88 ◽  
Author(s):  
Eva G. Bøgelund ◽  
Brett A. McGuire ◽  
Niels F. W. Ligterink ◽  
Vianney Taquet ◽  
Crystal L. Brogan ◽  
...  
Keyword(s):  
High Sensitivity ◽  
High Mass ◽  
Galactic Centre ◽  
Mass Star ◽  
Star Forming ◽  
Star Forming Regions ◽  
Low Mass ◽  
Low Levels ◽  
Grain Surface ◽  
Physical And Chemical

Context. The abundance of deuterated molecules in a star-forming region is sensitive to the environment in which they are formed. Deuteration fractions, in other words the ratio of a species containing D to its hydrogenated counterpart, therefore provide a powerful tool for studying the physical and chemical evolution of a star-forming system. While local low-mass star-forming regions show very high deuteration ratios, much lower fractions are observed towards Orion and the Galactic centre. Astration of deuterium has been suggested as a possible cause for low deuteration in the Galactic centre. Aims. We derive methanol deuteration fractions at a number of locations towards the high-mass star-forming region NGC 6334I, located at a mean distance of 1.3 kpc, and discuss how these can shed light on the conditions prevailing during its formation. Methods. We use high sensitivity, high spatial and spectral resolution observations obtained with the Atacama Large Millimeter/ submillimeter Array to study transitions of the less abundant, optically thin, methanol-isotopologues: 13CH3OH, CH318OH, CH2DOH and CH3OD, detected towards NGC 6334I. Assuming local thermodynamic equilibrium (LTE) and excitation temperatures of ~120–330 K, we derive column densities for each of the species and use these to infer CH2DOH/CH3OH and CH3OD/CH3OH fractions. Results. We derive column densities in a range of (0.8–8.3) × 1017 cm−2 for 13CH3OH, (0.13–3.4) × 1017 cm−2 for CH318OH, (0.03–1.63) × 1017 cm−2 for CH2DOH and (0.15–5.5) × 1017 cm−2 for CH3OD in a ~1″ beam. Interestingly, the column densities of CH3OD are consistently higher than those of CH2DOH throughout the region by factors of 2–15. We calculate the CH2DOH to CH3OH and CH3OD to CH3OH ratios for each of the sampled locations in NGC 6334I. These values range from 0.03% to 0.34% for CH2DOH and from 0.27% to 1.07% for CH3OD if we use the 13C isotope of methanol as a standard; using the 18 O-methanol as a standard, decreases the ratios by factors of between two and three. Conclusions. All regions studied in this work show CH2DOH/CH3OH as well as CH2DOH/CH3OD values that are considerably lower than those derived towards low-mass star-forming regions and slightly lower than those derived for the high-mass star-forming regions in Orion and the Galactic centre. The low ratios indicate a grain surface temperature during formation ~30 K, for which the efficiency of the formation of deuterated species is significantly reduced. Therefore, astration of deuterium in the Galactic centre cannot be the explanation for its low deuteration ratio but rather the high temperatures characterising the region.

scholarly journals Resolving the SELEX–LHCb double-charm baryon conflict: the impact of intrinsic heavy-quark hadroproduction and supersymmetric light-front holographic QCD

2019 ◽  
Vol 204 ◽  
pp. 08007
Author(s):  
Sergey Koshkarev ◽  
Stefan Groote
Keyword(s):  
Heavy Quark ◽  
Light Front ◽  
Charm Baryon ◽  
Holographic Qcd ◽  
Double Charm ◽  
The Impact

In this paper we review the hadroproduction mechanisms of doublecharm baryons for the different experimental environments and reinterpret the SELEX and LHCb results.

scholarly journals Light Particle and Quark Chemical Potentials from Negatively to Positively Charged Particle Yield Ratios Corrected by Removing Strong and Weak Decays

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Hai-Ling Lao ◽  
Ya-Qin Gao ◽  
Fu-Hu Liu
Keyword(s):  
Weak Decay ◽  
High Mass ◽  
Heavy Flavor ◽  
Proton Proton ◽  
Strange Quarks ◽  
Chemical Potentials ◽  
Rapidity Interval ◽  
Charged Pions ◽  
Energy Dependent ◽  
Positively Charged

The yield ratios of negatively to positively charged pions (π−/π+), negatively to positively charged kaons (K−/K+), and anti-protons to protons (p¯/p) produced in mid-rapidity interval in central gold-gold (Au-Au) collisions, central lead-lead (Pb-Pb) collisions, and inelastic (INEL) or non-single-diffractive (NSD) proton-proton (pp) collisions, as well as in forward rapidity region in INEL pp collisions are analyzed in the present work. Over an energy range from a few GeV to above 10 TeV, the chemical potentials of light flavor particles (pion, kaon, and proton) and quarks (up, down, and strange quarks) are extracted from the mentioned yield ratios in which the contributions of strong decay from high-mass resonance and weak decay from heavy flavor hadrons are removed. Most energy dependent chemical potentials show the maximum at about 4 GeV, while the energy dependent yield ratios do not show such an extremum.

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