We present the new nCTEQ15 set of nuclear parton distribution functions (PDFs) with uncertainties. This fit extends the CTEQ proton PDFs to include the nuclear dependence using data on nuclei all the ...way up to super(208) Pb. The uncertainties are determined using the Hessian method with an optimal rescaling of the eigenvectors to accurately represent the uncertainties for the chosen tolerance criteria. In addition to the deep inelastic scattering and Drell-Yan processes, we also include inclusive pion production data from the Relativistic Heavy Ion Collider to help constrain the nuclear gluon PDF. Furthermore, we investigate the correlation of the data sets with specific nuclear PDF flavor components and asses the impact of individual experiments. We also provide comparisons of the nCTEQ15 set with recent fits from other groups.
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We present a new set of leading-twist parton distribution functions, referred to as "CJ15," which take advantage of developments in the theoretical treatment of nuclear corrections as well as new ...data. The analysis includes, for the first time, data on the free neutron structure function from Jefferson Lab and new high-precision charged lepton and W-boson asymmetry data from Fermilab. These significantly reduce the uncertainty on the d/u ratio at large values of x and provide new insights into the partonic structure of bound nucleons.
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We demonstrate that theoretical predictions using current resummation techniques for the lepton pair production (LPP) rapidity and xF distributions can be inconsistent with data in high rapidity and ...xF kinematic regions by observing their effect in global fits of parton distribution functions (PDFs). We present an enhanced resummation technique for the LPP rapidity and xF distributions that agrees with LPP data. The enhanced resummation method is used in conjunction with threshold resummation in deep inelastic scattering to perform two global fits of PDFs using the minimal and Borel prescriptions. The results are analyzed to determine the effect of threshold resummation on global fits of PDFs.
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We review the present status of the determination of parton distribution functions (PDFs) in the light of the precision requirements for the LHC in Run 2 and other future hadron colliders. We provide ...brief reviews of all currently available PDF sets and use them to compute cross sections for a number of benchmark processes, including Higgs boson production in gluon–gluon fusion at the LHC. We show that the differences in the predictions obtained with the various PDFs are due to particular theory assumptions made in the fits of those PDFs. We discuss PDF uncertainties in the kinematic region covered by the LHC and on averaging procedures for PDFs, such as advocated by the PDF4LHC15 sets, and provide recommendations for the usage of PDF sets for theory predictions at the LHC.
The search for ferromagnetism above room temperature in dilute magnetic semiconductors has been intense in recent years. We report the first observations of ferromagnetism above room temperature for ...dilute (<4 at.%) Mn-doped ZnO. The Mn is found to carry an average magnetic moment of 0.16 mu(B) per ion. Our ab initio calculations find a valance state of Mn(2+) and that the magnetic moments are ordered ferromagnetically, consistent with the experimental findings. We have obtained room-temperature ferromagnetic ordering in bulk pellets, in transparent films 2-3 microm thick, and in the powder form of the same material. The unique feature of our sample preparation was the low-temperature processing. When standard high-temperature (T > 700 degrees C) methods were used, samples were found to exhibit clustering and were not ferromagnetic at room temperature. This capability to fabricate ferromagnetic Mn-doped ZnO semiconductors promises new spintronic devices as well as magneto-optic components.
We review the current status of spin-averaged and spin-dependent parton distribution functions (PDFs) of the nucleon. After presenting the formalism used to fit PDFs in modern global data analyses, ...we discuss constraints placed on the PDFs by specific data types. We give representative examples of unpolarized and polarized PDFs and their errors, and list open questions in global quantum chromodynamics fitting. Finally, we anticipate how future facilities, with fixed-target and collider experiments, may impact our knowledge of PDFs and reduce their uncertainties.
ABSTRACT
White striping is a condition associated with heavier broiler breast fillets and is observed grossly as white striations seen parallel to the direction of the muscle fibers. The present ...study was intended to assess the consumer acceptance of broiler fillets with different degrees of white striping condition. High resolution digital images of fillets, representative of varying degrees of white striping, were shown to 75 consumers in a blind study. Individual images were presented using a completely randomized design. There were 4 replicates of individual fillets within each white striping category (normal = NORM, moderate = MOD, and severe = SEV) and one picture of tray pack (3 fillets) for each category. The consumers were asked to express their overall liking for appearance with a 9-point hedonic scale (9 = like extremely; 1 = dislike extremely) and purchase intent using a 5-point scale (5 = definitely would buy; 1 = definitely would not buy). An open-ended comments section was also included. The results showed that NORM fillets had a significantly higher hedonic score (6.9) than the MOD fillets (6.1), which was also significantly higher than the SEV fillets (4.5), indicating that as severity of white striping increased, the consumer acceptance decreased. From the distribution of the responses, 10.7, 22.4, and 56.7% of the consumers disliked the NORM, MOD, and SEV fillets, respectively. Furthermore, the average purchase intent score for the NORM fillets (3.6) was significantly higher than those with 2 degrees of white striping (2.4 and 2.5, respectively), suggesting that the consumers were more likely to buy NORM fillets. Over 50% of the consumers indicated that they would probably not or definitely not buy MOD or SEV fillets. The correspondence analysis of open-ended comments revealed the major reasons for the dislike of the white-striped meat was that the fillets had a more fatty or marbled appearance. The results of the study suggest that the white striping does affect the consumer acceptance based on the appearance of the fillets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We present a new parton distribution function analysis which includes new data for W boson production in proton-proton collisions and lepton pair production in proton-proton and proton-deuteron ...collisions. The new data provide strong constraints on the light antiquark parton distribution functions in the proton. We identify an interesting correlation between the d/u ratio and the $\bar{d}$/$\bar{u}$ ratio which leads to a modification of our previous results for the d/u ratio as the parton momentum fraction x → 1.
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We discuss several advantages of using positron beams in addition to electron beams for the study of parton distribution functions (PDFs) of the nucleon in deep-inelastic scattering. Specific topics ...include the flavor separation of the unpolarized PDFs as well as the spin-dependent distributions.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An up-to-date global QCD analysis of high energy lepton-hadron and hadron-hadron interactions is performed to better determine the gluon and quark parton distributions in the nucleon. Improved ...experimental data on inclusive jet production, in conjunction with precise deep inelastic scattering data, place good constraints on the gluon over a wide range of x; while new data on asymmetries in Drell-Yan processes contribute to better determine the d/u ratio. Comparisons with results of other recent global analyses are made, and the differences are described. Open issues and the general problem of determining the uncertainties of parton distributions are discussed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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