共查询到20条相似文献,搜索用时 15 毫秒
1.
It has been conjectured that the relative phase between strong and electromagnetic amplitudes is universally-90° in charmonium decays. ψ' decaying into a pseudoscalar pair provides a possibility to test this conjecture. However, the experimentally observed cross section for such a process is depicted by the two-fold integral, which takes into account the initial state radiative (ISR) correction and energy spread effect. Using the generalized linear regression approach, a complex energy-dependent factor is approximated by a linear function of energy. Taking advantage of this simplification, the integration of ISR correction can be performed and an analytical expression with accuracy at the level of 1% is obtained. Then, the original two-fold integral is simplified into a one-fold integral, which reduces the total computing time by two orders of magnitude. Such a simplified expression for the observed cross section usually plays an indispensable role in the optimization of scan data taking, the determination of systematic uncertainty, and the analysis of data correlation. 相似文献
2.
It has been conjectured that the relative phase between strong and electromagnetic amplitudes is universally -90° in charmonium decays. ψ' decaying into a pseudoscalar pair provides a possibility to test this conjecture. However, the experimentally observed cross section for such a process is depicted by the two-fold integral, which takes into account the initial state radiative (ISR) correction and energy spread effect. Using the generalized linear regression approach, a complex energy-dependent factor is approximated by a linear function of energy. Taking advantage of this simplification, the integration of ISR correction can be performed and an analytical expression with accuracy at the level of 1% is obtained. Then, the original two-fold integral is simplified into a one-fold integral, which reduces the total computing time by two orders of magnitude. Such a simplified expression for the observed cross section usually plays an indispensable role in the optimization of scan data taking, the determination of systematic uncertainty, and the analysis of data correlation. 相似文献
3.
Agnieszka Grzelińska 《中国物理C(英文版)》2010,34(6)
We discuss interference effects important for the form factors extraction in the vicinity of J/ψ andψ(2S)resonances in combination with resonance parameters determination.The implementation to the Monte Carlo event generator PHOKHARA of the J/ψ and ψ(2S)contributions to the muon,pion and kaon pairs production associated with a photon at next-to-leading order is also described. 相似文献
4.
We discuss interference effects important for the form factors extraction in the vicinity of J/ψ and ψ(2S) resonances in combination with resonance parameters determination. The implementation to the Monte Carlo event generator PHOKHARA of the J/ψ and ψ(2S) contributions to the muon, pion and kaon pairs production associated with a photon at next-to-leading order is also described. 相似文献
5.
《中国物理C(英文版)》2019,(8)
We study the hadronic decays of ∧_c~+ to the final states ∑~+η and ∑~+η',using an e~+e~-annihilation data sample of 567 pb~(-1) taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCⅡ collider.We find evidence for the decays ∧_c~+→∑~+η and ∑~+η' with statistical significance of 2.5σ and 3.2σ,respectively.Normalizing to the reference decays ∧_c~+→∑~+π0 and ∑~+ω,we obtain the ratios of the branching fractions■and ■to be 0.35±0.16±0.02 and 0.86±0.34±0.04,respectively.The upper limits at the 90% confidence level are set to be■and■.Using BESIII measurements of the branching fractions of the reference decays,we determine B(∧_c~+→∑~+η)=(0.41±0.19±0.05)%(0.68%)and B(∧_c~+→∑~+η')=(1.34±0.53 ±0.19)%(1.9%).Here,the first uncertainties are statistical and the second systematic.The obtained branching fraction of ∧_c~+→∑~+η is consistent with the previous measurement,and the branching fraction of ∧_c~+→∑~+η' is measured for the first time. 相似文献
6.
It has been conjectured that the relative phase between strong and electromagnetic amplitudes is universally -90° in charmonium decays. ψ′ decaying into a pseudoscalar pair provides a possibility to test this conjecture. However, the experimentally observed cross section for such a process is depicted by the two-fold integral, which takes into account the initial state radiative (ISR) correction and energy spread effect. Using the generalized linear regression approach, a complex energy-dependent factor is ... 相似文献
7.
8.
We review some of our results obtained in the field of the structure of PT series in high orders and its resummation in some particular circumstances. 相似文献
9.
The world's largest sample of J/ψ events, 1.31 billion events accumulated at the BESIII detector, provides a unique opportunity to investigate η and η physics via two-body J/ψ radiative or hadronic decays. For many η decay channels the low background data samples are up to three orders of magnitude larger than collected in any previous experiment. Here we review the most significant results on η and η obtained at BESIII so far. The analyses range from detailed studies of common decay dynamics, observations of new radiative and Dalitz decays, and searches for rare/forbidden decays with sensitivity up to B~10-5. Finally, prospects of forthcoming runs at the J/ψ peak forη and η physics are discussed. 相似文献
10.
The light unflavoured meson η/η' decays are valuable for testing non-perturbative quantum chromodynamics and exploring new physics beyond the Standard Model. This paper describes a series of event generators, including η/η'→γl~+l~-, η/η'→γπ~+π~-, η'→ωe~+e~-, η→π~+π~-π~0, η/η'→π~0π~0π~0, η'→ηππ andη'→π~+π~-π~+π~-/π~+π~-π~0π~0, which have been developed for investigating η/ηdecay dynamics. For most of these generators, their usability has been validated in BESIII analyses for determining the detection efficiency, and background studies. The consistency between data and Monte Carlo shows that these generators work well in the BESⅢ simulation, and will also be useful for ongoing BESⅢ analyses and other experiments for studying η/η' physics. 相似文献
11.
《Physics letters. [Part B]》1999,446(2):125-134
12.
《中国物理C(英文版)》2017,(5)
In the past few decades,numerous searches have been made for the neutrinoless double-beta decay(0νββ) process,aiming to establish whether neutrinos are their own antiparticles(Majorana neutrinos),but no 0νββdecay signal has yet been observed.A number of new experiments are proposed but they ultimately suffer from a common problem: the sensitivity may not increase indefinitely with the target mass.We have performed a detailed analysis of the physics potential by using the Jiangmen Underground Neutrino Observatory(JUNO) to improve the sensitivity to 0νββ up to a few me V,a major step forward with respect to the experiments currently being planned.JUNO is a 20 kton low-background liquid scintillator(LS) detector with 3%/(E(MeV))1/2 energy resolution,now under construction.It is feasible to build a balloon filled with enriched xenon gas(with~(136)Xe up to 80%) dissolved in LS,inserted into the central region of the JUNO LS.The energy resolution is ~1.9% at the Q-value of ~(136)Xe 0νββ decay.Ultra-low background is the key for 0νββ decay searches.Detailed studies of background rates from intrinsic 2νββ and 8~B solar neutrinos,natural radioactivity,and cosmogenic radionuclides(including light isotopes and ~(137)Xe) were performed and several muon veto schemes were developed.We find that JUNO has the potential to reach a sensitivity(at 90% C.L.) to T_(1/2)~(0νββ)of 1.8×10~(28)yr(5.6×10~(27)yr) with ~50 tons(5 tons) of fiducial136 Xe and 5 years exposure,while in the 50-ton case the corresponding sensitivity to the effective neutrino mass,mββ,could reach(5–12) meV,covering completely the allowed region of inverted neutrino mass ordering. 相似文献
13.
Abundant ψ' events have been collected at the Beijing Electron Positron Collider-Ⅱ (BEPCⅡ) that could undoubtedly provide us with a great opportunity to study the more attractive charmonium decays. As has been noticed before, in the process of J/ψ' decaying to the baryonic final states, pK-Λ, the evident Λ* and N* bands have been observed. Similarly, by using the product of χcJ from ψ' radiative decay, we may confirm this or find some extra new resonances. χc0's data samples will be more than χc1,2, taking into account the larger branching ratio of ψ' →γχc0. Here, we provide explicit partial wave analysis formulae for the very interesting channel ψ' →γχc0 →γpK-Λ. 相似文献
14.
15.
Alejandro García 《Czechoslovak Journal of Physics》2000,50(4):485-487
Both l00Mo and 116Cd are double--decay candidates, whose intermediate (virtual) state is a nucleus with J
= 1+ in the ground state. Consequently, in these cases one can measure the single--decay matrix elements in addition to the 2-decay rate and test models in a more stringent way. We have measured the electron-capture decays of 100Tc and 116In which show that: a) the ground state dominance hypothesis works very well; b) deformation plays a role which cannot be neglected in QRPA calculations. QRPA predictions work better in the spherical A = 116 system than in the transition A = 100 system. 相似文献
16.
Ablikim M Achasov MN Alberto D Ambrose DJ An FF An Q An ZH Bai JZ Baldini Ferroli RB Ban Y Becker J Berger N Bertani MB Bian JM Boger E Bondarenko O Boyko I Briere RA Bytev V Cai X Calcaterra AC Cao GF Chang JF Chelkov G Chen G Chen HS Chen JC Chen ML Chen SJ Chen Y Chen YB Cheng HP Chu YP Cronin-Hennessy D Dai HL Dai JP Dedovich D Deng ZY Denysenko I Destefanis M Ding Ding WL Ding Y Dong LY Dong MY Du SX Fang J Fang SS Feng CQ Fu CD Fu JL Gao Y Geng C Goetzen K Gong WX Greco M Gu MH Gu YT 《Physical review letters》2012,108(18):182001
The decays J/ψ → γ π+ π- π0 and J/ψ → γ π0 π0 π0 are analyzed using a sample of 225×10(6) J/ψ events collected with the BESIII detector. The decay of η(1405) → f(0)(980)π0 with a large isospin violation is observed for the first time. The width of the f(0)(980) observed in the dipion mass spectra is anomalously narrower than the world average. Decay rates for three-pion decays of the η' are also measured precisely. 相似文献
17.
D. Delepine J. L. Lucio M. C. A. Ramírez 《The European Physical Journal C - Particles and Fields》2006,45(3):693-700
We analyze the
and B–,0 → f0K–,0 decays and show that a consistent phenomenological picture can be obtained within the factorization approximation. In this
approach the O6 operator provides the dominant contributions to the suppressed channel
. An estimate of the annihilation form factor using perturbative QCD indicates that this contribution is not negligible, moreover
interference with other penguin contributions includes a free parameter since the phase of the annihilation amplitude is not
determined. Assumptions based on SU(2) isospin symmetry provide relations between different B decays involving one scalar and one pseudoscalar meson. 相似文献
18.
《中国物理C(英文版)》2010,(6)
The D0-0 mixing at Belle in different modes with corresponding methods is reported in this paper,there is a clear evidence for non-zero y D0 mixing parameter,and the measurement of D0 mixing parameter x is still a challenge.CP violation in the decays is not observed.Branching fractions of other charm decays are presented. 相似文献
19.
The three-body decays χ b0,2 → J/ ψc $\bar c$ and the decays x bJ → J/ ψD $\bar D$ related to them are studied. The differential widths with respect to these decays are calculated analytically, and their total widths are evaluated numerically. The duality relation between these decays and the two-body decays x b0,2 → J/ ψ(c $\bar c$ ) is verified. The possibility of observing these decays at the LHC and Tevatron colliders is discussed. 相似文献
20.