Hauptseite: Unterschied zwischen den Versionen

Aus AngelnPedia
Wechseln zu: Navigation, Suche
K
K
Zeile 1: Zeile 1:
The latest analyses [1221,1222] show pretty great agreement with J/ photoproduction data at HERA [1169?171,1185] and hadroproduction in the LHC [1142,1144,1182]. On leading of that, the J/ is predicted to be largely unpolarized, in line with all recent polarization measurements; see paragraph d in Sect. 4.five.1. As for hadroproduction, the conclusions are even so contrary to the author's earlier findings [1223], which show longitudinal J/ polarization and cross sections an order of magnitude beneath the CDF production information. In addition they disagree with all the current perform [1224], exactly where J/ hadroproduction at the LHC was studied in the same way, comparing for the exact same data [1142,1144,1182], even when precisely the same uPDFs [1225,1226]2981 Page 80 of 241 Table 14 Colour singlet model predictions for (e+ e- J/ + c ) in comparison with B-factory information [1204?206]. As for the theoretical predictions for the leading-order cross section at the same time because the corrections of order O(s ), O(v 2 ), and O(s v two ), we evaluate the outcomes obtained [https://dx.doi.org/10.1098/rstb.2015.0074 title= rstb.2015.0074] in [1207?209]. These calculations mostly differ by distinctive strategies of colour singlet LDME determinations. As for the values of [1208], the leading-order results contain pure QED contributions, the O(s ) He, Fan, Chao [1207] s (2m c ) L O  (s )  (v two )  (s v two ) sum Belle [1204] Belle [1205] BaBar [1206] 20.0 fb 9.0 fb eight.8 fb 2.2 fbEur. Phys. J. C (2014) 74:2981 outcomes contain interference terms with the QED contributions, plus the O(v 2 ) final results involve in aspect a resummation of relativistic corrections, the O(s v 2 ) outcomes do, nevertheless, consist of the interference terms on the O(s ) and O(v two ) amplitudes only. The short-distance coefficients with the O(s ) [https://www.medchemexpress.com/cpi-203.html CPI-203 chemical information] contribution employed in [1207] and [1208] were taken over from [1210]. The experimental cross sections refer to information samples in which at [https://dx.doi.org/10.1089/jir.2014.0001 title= jir.2014.0001] least 2, respectively 4, charged tracks had been identified Li, Wang [1209] s ( s/2) four.381 fb 5.196 fb 1.714 fb 0.731 fb 12.022 fb (4 charged tracks) s (2m c ) 7.0145 fb 7.367 fb 2.745 fb 0.245 fb 17.372 fbBodwin, Lee,Yu [1208] s ( s/2) six.4 fb six.9 fb two.9 fb 1.4 fb 17.6+8.1 fb -6.7 33+7 ?9 fb -25.six ?2.8 ?3.four fb (2 charged tracks) 17.6 ?2.8+1.five fb (2 charged tracks) -2.have been employed. Right here, the colour singlet predictions lie once more clearly under the data, as well as the distinction was even utilised to match the CO LDMEs of NRQCD in a kT factorization approach. We note that calculations inside the kT factorization scheme is often performed for any intermediate Fock state in the NRQCD v expansion. Alternatively, even a completely worked out framework of kT factorization at NLO in s could not remedy the problem of uncanceled infrared singularities in colour singlet model calculations for P wave quarkonia.tigated, as might be noticed from contradicting kT factorization final results.
+
Shold, enhancing our understanding from the dynamics of these systems and
 +
Shold, improving our understanding with the dynamics of those systems and [http://girl-fridayblog.com/helping-hands/p/290065/ http://girl-fridayblog.com/helping-hands/p/290065/] giving, amongst others, precision determinations on the powerful coupling constant at low energies along with the heavy quark masses. For states at and above threshold, they might eventually be capable of ascertain the nature of the X Y Z exotic states, such as in distinct the part that mixing amongst tetraquark and multihadron states plays. A achievable solution to address these difficulties that relies on lattice simulations has been really not too long ago proposed in [1230,1231]. Lattice simulations are also necessary for figuring out non-perturbative type components needed in extracting the CKM matrix components |Vcb |, |Vub |, |Vcs | and |Vcd | from B D /l and D K /l decays, respectively. Existing gaps amongst lattice determinations and experimental fits of these form variables are anticipated to be removed by further progress in lattice simulations. The4.5.5 Existing trends in theory The most prominent candidate theory for heavy quarkonium production is NRQCD, and a lot of effort is going on to prove its factorization [https://dx.doi.org/10.1098/rstb.2015.0074 title= rstb.2015.0074] theorem on the one particular hand, and to show the universality with the LDMEs by comparison to data on the other. Considering the fact that at the moment you'll find hints that at the least towards the orders currently regarded as in perturbation theory, not all data might be simultaneously described by single LDME sets, much more work are going to be going on to refine NRQCD calculations for [https://dx.doi.org/10.3389/fpsyg.2017.00209 title= fpsyg.2017.00209] precise observables or certain kinematic regimes, for instance the low and higher pT limits of the hadroproduction cross sections. For low pT resummation of big logarithms, the recent work [1227] followed the concept of [1228] to apply the Collins oper terman effect parameter resummation formalism [90]. For higher pT resummation, the factorization theorem of [781,783] when it comes to single and double parton fragmentation functions, and the soft-collinear effective theory method [785,786] can be applied. Other paths may be to apply transverse momentum-dependent PDFs in quarkonium production calculations, but the uncertainties inherent to these calculations will still must be thoroughly inves-Eur. Phys. J. C (2014) 74:Web page 81 of 241emergence of ensembles incorporating the effects of dynamical charm quarks in lattice calculations will enable to establish whether or not charm sea contributions to charmonium spectra and to flavor observables are relevant. At the very same time, the trend to finer lattice spacings (even if at present somewhat displaced by a trend to perform simulations in the physical pion mass) is likely to continue within the long run and will eventually enable the use of totally relativistic b-quarks, which will supply a crucial cross-check on powerful field theories, and at some point for some observables replace them. Rapid progress on the side of successful field theories is at present taking place for any system involving heavy quarks. Many quantities, like spectra, decays, transitions and production cross sections, are computed within this framework with unprecedented precision within the velocity and s expansions. Noteworthy progress is happening, in certain, inside the field of quarkonium production. Right here, the current Snowmass White Paper on "Quarkonium at the Frontiers of High Energy Physics" [1013] offers a great summary.

Version vom 3. Januar 2018, 06:58 Uhr