107 research outputs found
Thermal conductivity factor for beef of NOR and DFD grades at the subcryoscopic temperatures
No full textThermal conductivity factor and specific isobaric heat capacity of food products are currently the most important parameters in the development of mathematical models for food freezing and thawing and in improving production technology. There is significant variance among the existing experimental data for the thermal conductivity factor in meat. Most of the modern calculated relationships are based on the nutritional approach, which favorably differs by the ability to calculate the thermophysical characteristics of any food products. However, the calculation error at the subcryoscopic temperatures may be 15% to 20%. The development of superchilling as a way of storing meat requires high accuracy of freezing time calculation, including vacuumpacked boneless meat. In the presented article, the authors investigated hydrogen index, cryoscopic temperature, frozen moisture proportion and thermal conductivity factor for beef M. longissimus dorsi samples of NOR and DFD grades. It was found that DFD beef is characterized by 10% to 12% higher values of thermal conductivity factor in comparison with NOR grade. Using the method of regression analysis, the authors developed empirical relationships for calculating the thermal conductivity factor of meat depending on its temperature and pH level. Unlike cryoscopic temperature and frozen moisture proportion, pH is easy to measure and may be easily used on a conveyor belt for more accurate assessment of meat thermophysical properties. With an increase in pH from 5.3 to 7, an increase in cryoscopic temperature is observed from minus 0.94 °C to minus 0.72 °C. It has been shown that one of the factors for the higher cryoscopic temperature and higher pH level of DFD beef is higher water-holding capacity with less strongly bound moisture
The K
No full textThe K0
SK0
S final state in two-photon collisions is studied with the L3 experiment at LEP, using orbital angular momentum operators. The mass spectrum is dominated by the formation of tensor mesons, their two-photon partial width are determined. A signal at 1700-1800MeV is found to be a new tensor state f
2(1750) with mass M = (1755±10)MeV and width Γ = (67±12)MeV. All observed tensor resonances obey SU(3) relations. The f
2(1750) state forms a second tensor nonet together with f
2(1560) and a
2(1700). The SU(3) analysis allows us to determine with good accuracy mixing angles between nonstrange and strange components of the isoscalar members of tensor nonets
Partial wave analysis of anti-p p annihilation channels in flight with I = 1, C = +1
No full textAbstractA combined analysis is reported of 3π0, π0η and π0η′ data in the mass range 1960 to 2410 MeV. This analysis is made consistent also with ηηπ0 data, reported separately. The analysis requires s-channel resonances with a spectrum close to that published earlier for C=+1 states with I=0; masses for I=1 states are lower on average by 20 MeV. Two alternative solutions are found, differing only for JP=2+ and 4+ states by small amounts in masses and widths. Both 3π0 and ηπ0 data prefer one of these two solutions. For this preferred solution, observed states have JPC, masses and widths (M,Γ) in MeV as follows: 4−+: (2250±15, 215±25), 4++: (2255±40, 330+110−50) and (2005+25−45, 180±30), 3++: (2275±35, 350+100−50) and (2031±12, 150±18), 2−+: (2245±60, 320+100−40) and (2005±15, 200±40), 2++: (2255±20, 230±15), (2175±40, 310+90−45) and (2030±20, 205±30), and 1++: (2270+55−40, 305+70−35). There are indications of further 2−+, 2++ and 1++ contributions just below the available mass range, and also a 0++ state at ∼2025 MeV
Bridging Time-Like and Space-Like N* Form Factors
No full textInternational audienceThe study of electromagnetic transitions opens a window into the very nature of the strong interaction. And, indeed, such a study of how a ground-state nucleon transitions to an excited state, over a broad range of , will provide keen insight into the evolution of how dynamically-generated masses emerge from the asymptotically-free, nearly massless quarks of perturbative QCD as well as provide information on the ancillary effects from the meson–baryon cloud. The space-like ( ) region at GSI. We are living in exciting times whereby near-future prospects exist in extracting high-quality data in both the space-like and time-like regimes (JLab12 and FAIR, for example). The recent ECT* workshop, entitled space-like and time-like electromagnetic baryonic transitions, brought together several disparate communities of experimentalists and theorists. The goal and purpose of this workshop was to make the very first steps towards a much needed consistent description spanning the two kinematical regimes in . The discussions included photoproduction measurements (ELSA, JLab, LEPS, and MAMI), wherein the point anchors the connection between space-like and time-like regions and meson-beam data (GSI and J-PARC) and amply complements the requisite information for baryon spectroscopy. This paper presents the outcomes from this ECT* workshop, space-like and time-like baryon electromagnetic transitions, held at the European Centre for Theoretical Studies in Nuclear Physics and Related Areas in Trento, Italy, May 8–12, 2017
Measurement of the helicity asymmetry E for the γ→ p→ → pπ reaction in the resonance region: The CLAS Collaboration
No full textThe double-spin-polarization observable E for γ→ p→ → pπ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies Eγ from 0.367 to 2.173GeV (corresponding to center-of-mass energies from 1.240 to 2.200GeV) for pion center-of-mass angles, cosθπ0c.m. , between - 0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina groups. Their inclusion in multipole analyses will allow us to refine our understanding of the single-pion production contribution to the Gerasimov-Drell-Hearn sum rule and improve the determination of resonance properties, which will be presented in a future publication
Observation of f0(1770) -> eta-eta in pbar-p -> eta-eta-pizero reactions from 600 to 1200 MeV/c
No full textWe present data on pbar-p -> eta-eta-pizero at beam momenta of 600, 900, 1050, and 1200 MeV/c. At the higher three momenta, a signal is clearly visible due to pbar-p -> f_0(1770)-pizero, f_0(1770) -> eta-eta. It has mass 1770+-12 MeV and width 220+-40 MeV, where errors cover systematic uncertainties as well as statistics.We present data on p ̄ p→ηηπ 0 at beam momenta of 600, 900, 1050, and 1200 MeV/ c . At the higher three momenta, a signal is clearly visible due to p ̄ p→f 0 (1770)π 0 , f 0 (1770)→ηη . It has mass 1770±12 MeV and width 220±40 MeV, where errors cover systematic uncertainties as well as statistics.We present data on pbar-p -> eta-eta-pizero at beam momenta of 600, 900, 1050, and 1200 MeV/c. At the higher three momenta, a signal is clearly visible due to pbar-p -> f_0(1770)-pizero, f_0(1770) -> eta-eta. It has mass 1770+-12 MeV and width 220+-40 MeV, where errors cover systematic uncertainties as well as statistics
Partial wave analysiss of pbar-p -> piminus-piplus, pizero-pizero, eta-eta and eta-etaprime
No full textA partial wave analysis is presented of Crystal Barrel data on pbar-p -> pizero-pizero, eta-eta and eta-etaprime from 600 to 1940 MeV/c, combined with earlier data on d\sigma /d\Omega and P for pbar-p->piminus-piplus. The following s-channel I=0 resonances are identified: (i) J^{PC} = 5^{--} with mass and width (M,\Gamma) at (2295+-30,235^{+65}_{-40}) MeV, (ii) J^{PC} = 4^{++} at (2020+-12, 170+-15) MeV and (2300+-25, 270+-50) MeV, (iii) 3D3 JPC = 3^{--} at (1960+-15, 150+-25) MeV and (2210+-4, 360+-55) MeV, and a 3G3 state at (2300 ^{+50}_{-80}, 340+-150) MeV, (iv) JPC = 2^{++} at (1910+-30, 260+-40) MeV, (2020+-30, 275+-35) MeV, (2230+-30, 245+-45) MeV, and (2300+-35, 290+-50) MeV, (v) JPC = 1^{--} at (2005+-40, 275+-75) MeV, and (2165+-40, 160 ^{+140}_{-70}) MeV, and (vi) JPC = 0^{++} at (2005+-30, 305+-50) MeV, (2105+-15, 200+-25) MeV, and (2320+-30, 175+-45) MeV. In addition, there is a less well defined 6^{++} resonance at 2485+-40 MeV, with Gamma = 410+-90 MeV. For every JP, almost all these resonances lie on well defined linear trajectories of mass squared v. excitation number. The slope is 1.10+-0.03 Gev^2 per excitation. The f_0(2105) has strong coupling to eta-\eta, but much weaker coupling to pizero-pizero. Its flavour mixing angle between q-qbar and s-sbar is (59-71.6)deg, i.e. dominant decays to s-sbar. Such decays and its strong production in pbar-p interactions strongly suggest exotic character.A partial wave analysis is presented of Crystal Barrel data on p ̄ p→π 0 π 0 , ηη and ηη′ from 600 to 1940 MeV/c, combined with earlier data on dσ/dΩ and P for p ̄ p→π − π + . The following s -channel I=0 resonances are identified: (i) J PC =5 −− with mass and width ( M , Γ ) at ( 2295±30 , 235 +65 −40 ) MeV, (ii) J PC =4 ++ at ( 2020±12 , 170±15 ) MeV and ( 2300±25 , 270±50 ) MeV, (iii) 3 D 3 J PC =3 −− at ( 1960±15 , 150±25 ) MeV and ( 2210±40 , 360±55 ) MeV, and a 3 G 3 state at ( 2300 +50 −80 ,340±150) MeV, (iv) J PC =2 ++ at ( 1910±30 , 260±40 ) MeV, ( 2020±30 , 275±35 ) MeV, ( 2230±30 , 245±45 ) MeV, and ( 2300±35 , 290±50 ) MeV, (v) J PC =1 −− at ( 2005±40 , 275±75 ) MeV, and ( 2165±40 , 160 +140 −70 ) MeV, and (vi) J PC =0 ++ at ( 2005±30 , 305±50 ) MeV, ( 2105±15 , 200±25 ) MeV, and ( 2320±30 , 175±45 ) MeV. In addition, there is a less well defined 6 ++ resonance at 2485±40 MeV, with Γ=410±90 MeV. For every J P , almost all these resonances lie on well defined linear trajectories of mass squared versus excitation number. The slope is 1.10±0.03 GeV 2 per excitation.A partial wave analysis is presented of Crystal Barrel data on pbar-p -> pizero-pizero, eta-eta and eta-etaprime from 600 to 1940 MeV/c, combined with earlier data on d\sigma /d\Omega and P for pbar-p->piminus-piplus. The following s-channel I=0 resonances are identified: (i) J^{PC} = 5^{--} with mass and width (M,\Gamma) at (2295+-30,235^{+65}_{-40}) MeV, (ii) J^{PC} = 4^{++} at (2020+-12, 170+-15) MeV and (2300+-25, 270+-50) MeV, (iii) 3D3 JPC = 3^{--} at (1960+-15, 150+-25) MeV and (2210+-4, 360+-55) MeV, and a 3G3 state at (2300 ^{+50}_{-80}, 340+-150) MeV, (iv) JPC = 2^{++} at (1910+-30, 260+-40) MeV, (2020+-30, 275+-35) MeV, (2230+-30, 245+-45) MeV, and (2300+-35, 290+-50) MeV, (v) JPC = 1^{--} at (2005+-40, 275+-75) MeV, and (2165+-40, 160 ^{+140}_{-70}) MeV, and (vi) JPC = 0^{++} at (2005+-30, 305+-50) MeV, (2105+-15, 200+-25) MeV, and (2320+-30, 175+-45) MeV. In addition, there is a less well defined 6^{++} resonance at 2485+-40 MeV, with Gamma = 410+-90 MeV. For every JP, almost all these resonances lie on well defined linear trajectories of mass squared v. excitation number. The slope is 1.10+-0.03 Gev^2 per excitation. The f_0(2105) has strong coupling to eta-\eta, but much weaker coupling to pizero-pizero. Its flavour mixing angle between q-qbar and s-sbar is (59-71.6)deg, i.e. dominant decays to s-sbar. Such decays and its strong production in pbar-p interactions strongly suggest exotic character
Study of the decay J/ψ →φπ0η
No full textBased on (10.09±0.04)×109 J/ψ events collected with the BESIII detector operating at the BEPCII collider, a partial wave analysis of the decay J/ψ→φπ0η is performed. We observe for the first time two new structures on the φη invariant mass distribution, with significances exceeding 27σ and 13σ; the first with JPC=1+-, mass M=(1908±6(stat) -4+8(sys)) MeV/c2, and width Γ=(175±13(stat) -16+7(sys)) MeV, the second with JPC=1 - , mass M=(1992±12(stat) -6+15(sys)) MeV/c2, and width Γ=(132±22(stat) -4+17(sys)) MeV. These measurements provide important input for the strangeonium spectrum. In addition, the f0(980)-a0(980)0 mixing signal in J/ψ→φf0(980)→φa0(980)0 and the corresponding electromagnetic decay J/ψ→φa0(980)0 are measured with improved precision, providing crucial information to understand the nature of a0(980)0 and f0(980)
Measurement of the proton form factor by studying e+e- →p p ̄
No full textUsing data samples collected with the BESIII detector at the BEPCII collider, we measure the Born cross section of e+e- --> ppbar at 12 center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective electromagnetic form factor of the proton is deduced under the assumption that the electric and magnetic form factors are equal (|GE|=|GM|). In addition, the ratio of electric to magnetic form factors, |GE/GM|, and |GM| are extracted by fitting the polar angle distribution of the proton for the data samples with larger statistics, namely at sqrt(s)=2232.4 and 2400.0 MeV and a combined sample at sqrt(s)=3050.0, 3060.0 and 3080.0 MeV, respectively. The measured cross sections are in agreement with recent results from BABAR, improving the overall uncertainty by about 30%. The |GE/GM| ratios are close to unity and consistent with BABAR results in the same q2 region, which indicates the data are consistent with the assumption that |GE|=|GM| within uncertainties
Search for a scalar partner of the X(3872) via ψ(3770) decays into γηη′ and γπ+π−J/ψ
No full textUsing a data sample corresponding to an integrated luminosity of 2.93 fb−1 collected at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider, we search for a scalar partner of the X(3872), denoted as X(3700), via ψ(3770) → γηη0 and γπ+π−J/ψ processes. No significant signals are observed and the upper limits of the product branching fractions B(ψ(3770) → γX(3700)) · B(X(3700) → ηη0) and B(ψ(3770) → γX(3700)) · B(X(3700) → π+π−J/ψ) are determined at the 90% confidence level, for the narrow X(3700) with a mass ranging from 3710 to 3740 MeV/c2, which are from 0.9 to 1.9(×10−5) and 0.9 to 3.4(×10−5), respectively
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