ANALYSIS OF D→ππ BEYOND NAIVE FACTORIZATION

2004 ◽  
Vol 19 (21) ◽  
pp. 1623-1631 ◽  
Author(s):  
XIANG-YAO WU ◽  
XIN-GUO YIN ◽  
DE-BAO CHEN ◽  
YI-QING GUO ◽  
YU ZENG

We analyze the D→ππ decay channels at the leading order, αs corrections with the QCD factorization and the soft-gluon corrections with the light cone QCD sum rule. Comparing with the experimental result, the calculations of the D0→π+π- and D+→π+π0 decay are much better under the consideration of the contributions of factorization parts, αs corrections and soft-gluon effects. However, the calculation result is one order less than the experimental result in D0→π0π0 decay. It may have large effects of final state interaction in the decay channel.

2016 ◽  
Vol 31 (14n15) ◽  
pp. 1650079
Author(s):  
Amin Asadi ◽  
Hossein Mehraban

In this paper, we analyzed the process of [Formula: see text] decay within QCD factorization (QCDF) and final state interaction (FSI) effects. At first, the [Formula: see text] decay is calculated via QCDF approach. The result that is found by using the QCDF method is less than the experimental result. Then we considered FSI effect as a sizable correction where there are the intermediate state [Formula: see text] mesons via the exchange of [Formula: see text]. The experi mental branching ratio of [Formula: see text] decay is [Formula: see text], and our results by QCDF and FSI are [Formula: see text] and [Formula: see text], respectively.


2014 ◽  
Vol 92 (11) ◽  
pp. 1400-1404
Author(s):  
Hossein Mehraban ◽  
Amin Asadi

In this article the exclusive decay of [Formula: see text] is calculated using the QCD factorization (QCDF) method and final state interaction (FSI). First, the [Formula: see text] decay is calculated via the QCDF method and only the annihilation graphs exist in that method. The result found using the QCDF method is lower than the experimental result. FSI is considered to solve the [Formula: see text] decay. For this decay, D+K0, D0K+, and [Formula: see text] via the exchange of K0, K+, and [Formula: see text] are chosen for the intermediate states and we calculate B+ → D+K0 → [Formula: see text] decay. The amplitude of B+ → D+K0 decay is calculated using the QCDF method again. The experimental branching ratio of [Formula: see text] decay is less than 1.2 × 10−5 and our results calculated using the QCDF method and FSI are (0.4 ± 0.06) × 10−7 and (0.93 ± 0.08) × 10−5, respectively.


2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Behnam Mohammadi ◽  
Hossein Mehraban

The exclusive decay ofB+→J/ψρ+is studied in the framework of the QCD factorization (QCDF) method and final state interaction (FSI). A directB+→J/ψρ+decay is only occurred via a tree and a penguin based on the quark diagram analysis. The result that is found by using the QCDF method is less than the experimental result, so, the role of FSI is considered. The intermediate statesD+D̅0,D+*D̅0*,D+*D̅0, andD+D̅0*via the exchange ofD-andD-*are contributed to theB+→J/ψρ+decay. The above intermediate states is calculated by using the QCDF method. In the FSI effects the results of our calculations depend on “η” as the phenomenological parameter. The range of this parameter are selected from 1 to 2. For the exchanged particlesD-andD-*, it is found that ifη=1.58~1.83is selected the numbers of the branching ratio are placed in the experimental range. The experimental branching ratio ofB+→J/ψρ+decay is(5±0.8)×10-5, and our prediction number is(1.42±0.36)×10-5in the absence of FSI effects, and it becomes(4.2~5.8)×10-5when FSI contributions are taken into account.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Edmond Iancu ◽  
Yair Mulian

Abstract Using the CGC effective theory together with the hybrid factorisation, we study forward dijet production in proton-nucleus collisions beyond leading order. In this paper, we compute the “real” next-to-leading order (NLO) corrections, i.e. the radiative corrections associated with a three-parton final state, out of which only two are being measured. To that aim, we start by revisiting our previous results for the three-parton cross-section presented in [1]. After some reshuffling of terms, we deduce new expressions for these results, which not only look considerably simpler, but are also physically more transparent. We also correct several errors in this process. The real NLO corrections to inclusive dijet production are then obtained by integrating out the kinematics of any of the three final partons. We explicitly work out the interesting limits where the unmeasured parton is either a soft gluon, or the product of a collinear splitting. We find the expected results in both limits: the B-JIMWLK evolution of the leading-order dijet cross-section in the first case (soft gluon) and, respectively, the DGLAP evolution of the initial and final states in the second case (collinear splitting). The “virtual” NLO corrections to dijet production will be presented in a subsequent publication.


2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Zhan Sun

Abstract In this paper, we present a detailed next-to-leading-order (NLO) study of J/ψ angular distributions in e+e−→ J/ψ + ηc, χcJ (J = 0, 1, 2) within the nonrelativistic QCD factorization (NRQCD). The numerical NLO expressions for total and differential cross sections, i.e., $$ \frac{d\sigma}{d\cos \theta } $$ dσ d cos θ = A + B cos2θ, are both derived. With the inclusion of the newly-calculated QCD corrections to A and B, the αθ (= B/A) parameters in J/ψ + χc0 and J/ψ + χc1 are moderately enhanced, while the magnitude of αθJ/ψ+χc2 is significantly reduced; regarding the production of J/ψ + ηc, the αθ value remains unchanged. By comparing with experiment, we find the predicted αθJ/ψ+ηc is in good agreement with the Belle measurement; however, αθJ/ψ+χc0 is still totally incompatible with the experimental result, and this discrepancy seems to hardly be cured by proper choices of the charm-quark mass, the renormalization scale, and the NRQCD matrix elements.


2019 ◽  
Vol 204 ◽  
pp. 06007
Author(s):  
Valery V. Lyuboshitz ◽  
Vladimir L. Lyuboshitz

The phenomenological structure of inclusive cross-sections of the production of two neutral K mesons in hadron–hadron, hadron–nucleus and nucleus–nucleus collisions is theoretically investigated taking into account the strangeness conservation in strong and electromagnetic interactions. Relations describing the dependence of the correlations of two short-lived and two long-lived neutral kaons $K_S^0K_S^0,K_L^0K_L^0$ and the correlations of “mixed” pairs $K_S^0K_L^0$ at small relative momenta upon the space-time parameters of the generation region of K0 and K̅0 mesons have been obtained. These relations involve the contributions of Bose-statistics and S -wave strong final-state interaction of two K0 (K̅0) mesons as well as of the K0 and K̅0 mesons, and also the additional contribution of transitions K+K– → K0 K̅0, and they depend upon the relative fractions of generated pairs K0K0, K̅0 K̅0 and K0 K̅0. It is shown that under the strangeness conservation the correlation functions of the pairs $K_S^0K_S^0$ and $K_L^0K_L^0$, produced in the same inclusive process, coincide, and the difference between the correlation functions of the pairs $K_S^0K_S^0$ and $K_S^0K_L^0$ is conditioned exclusively by the production of the pairs of non-identical neutral kaons K0 K̅0. For comparison, analogous correlations for the pairs of neutral heavy mesons D0, B0 and $B_s^0$, generated in multiple inclusive processes with charm (beauty) conservation, are also theoretically analyzed. These correlations are described by quite similar expressions: in particular, just as for K0 mesons, the correlation functions for the pairs of states with the same CP parity (RS S = RLL) and with different CP parity (RS L) do not coincide, and the difference between them is conditioned exclusively by the production of pairs D0 D̅0, B0B̅0 and $B_s^0\bar B_s^0$. However, contrary to the case of K0 mesons, here the distinction of CP-even and CP-odd states encounters difficulties – due to the insignificant differences of their lifetimes and the relatively small probability of purely CP-even and CP-odd decay channels. Nevertheless, one may hope that it will become possible at future colliders.


2015 ◽  
Vol 30 (36) ◽  
pp. 1550222
Author(s):  
Amin Asadi ◽  
Hossein Mehraban

In this paper, we analyzed the decay [Formula: see text] within QCD factorization (QCDF) and final state interaction (FSI) methods. At first, we consider the QCDF approach, where the final states are a pseudoscalar meson and vector meson. Then, we consider the FSI method where the intermediate states are [Formula: see text] and [Formula: see text] via the exchange of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] to improve the branching ratio. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on [Formula: see text] as the phenomenological parameter. The experimental branching ratio of this decay is [Formula: see text]. Our results in QCDF approach is [Formula: see text], and with [Formula: see text], the improved branching ratio is [Formula: see text].


2012 ◽  
Vol 27 (11) ◽  
pp. 1250064 ◽  
Author(s):  
BEHNAM MOHAMMADI ◽  
HOSSEIN MEHRABAN

In this research, the hadronic decay of [Formula: see text] is analyzed by using "QCD factorization" (QCDF) method and final state interaction (FSI). First, the [Formula: see text] decay is calculated via QCDF method and only the annihilation graphs exist in that method. Then, FSI is considered to solve the [Formula: see text] decay as a sizable correction and the D+*K0, D0*K+ and [Formula: see text] via the exchange of [Formula: see text], K-(*) and [Formula: see text] mesons are chosen for the intermediate states. To estimate the intermediate states amplitudes, QCDF method is again used. These amplitudes are used in the absorptive part of the diagrams. The experimental branching ratio of [Formula: see text] decay is less than 1.9×10-6 and our results according to QCDF method and FSI effects are 0.16×10-6 and 1.86×10-6, respectively.


2014 ◽  
Vol 26 ◽  
pp. 1460109
Author(s):  
MARINA NIELSEN ◽  
RAPHAEL M. ALBUQUERQUE ◽  
SU HOUNG LEE

We study, using the QCD sum rule framework, the possible existence of a charmed pentaquark that we call Θc(3250). In the QCD side we work at leading order in αs and consider condensates up to dimension 10. The mass obtained: mΘc = (3.21±0.13) GeV, is compatible with the mass of the structure seen by BaBar Collaboration in the decay channel [Formula: see text].


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
M. M. Almarashi

We study the a 1 a 1 and Z a 1 decay channels of the next-to-lightest CP-even Higgs boson h 2 of the NMSSM at the LHC, where the h 2 is produced in gluon fusion. It is found that while the h 2 discovery is impossible through the latter channel, the former one in the 4 τ final state is a promising channel to discover the h 2 with masses up to around 250 GeV at the LHC. Such a discovery of the h 2 is mostly accompanied with a light a 1 , which is a clear evidence for distinguishing the NMSSM from the MSSM since such a light a 1 is impossible in the MSSM.


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