scholarly journals Prompt production of the hidden charm pentaquarks in the LHC

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Pan Ling ◽  
Xiao-Hu Dai ◽  
Meng-Lin Du ◽  
Qian Wang

AbstractMotivated by the observation of the first hidden charm pentaquarks by the LHCb collaboration in 2015 and the updated analysis with an order-of-magnitude larger data set in 2019, we estimate their cross sections for the prompt production as well as their heavy quark spin partners, in the $$\Sigma _c^{(*)}\bar{D}^{(*)}$$ Σ c ( ∗ ) D ¯ ( ∗ ) hadronic molecular picture, at the center-of-mass energy $$7~\text {TeV}$$ 7 TeV in the pp collision. Their cross sections are several $${\mathrm {nb}}$$ nb and we would expect several tens hidden charm pentaquark events in the LHC based on its current integrated luminosity. The cross sections show a sizable deviation of the cross sections for hidden charm pentaquarks with the third isospin component $$I_z=+\frac{1}{2}$$ I z = + 1 2 ($$P_c^+$$ P c + ) from those with $$I_z=-\frac{1}{2}$$ I z = - 1 2 ($$P_c^0$$ P c 0 ). The cross sections decrease dramatically with the increasing transverse momentum. Our study can also tell where to search for the missing hidden charm pentaquarks. The confirmation of the complete hidden charm pentaquarks in the heavy quark symmetry would further verify their $$\Sigma _c^{(*)}\bar{D}^{(*)}$$ Σ c ( ∗ ) D ¯ ( ∗ ) molecular interpretation. In addition, the relative strength among these cross sections for pentaquarks can help us to identify the quantum numbers of the $$P_c(4440)$$ P c ( 4440 ) and $$P_c(4457)$$ P c ( 4457 ) .

2018 ◽  
Vol 172 ◽  
pp. 03002
Author(s):  
Haiming HU

The measurements of hadronic form factors of three modes using the data samples collected with the BESIII detector at BEPCII collider are presented. The cross section of e+e- → p p̅ at 12 energies from 2232.4 to 3671.0 MeV are measured, the electromagnetic form factor is deduced, and the ratio |GE/GM| is extracted by fitting the polar angle distribution. The preliminary results about the form factors of e+e- → ∧c+ ⊼c- will also be described. The cross section of e+e- → π+ π-between effective center-of-mass energy 600 and 900 MeV is measured by the ISR return method using the data set with the integrated luminosity of 2.93 fb-1 taken at ψ(3773) peak, the pion form factor is extracted.


2019 ◽  
Vol 212 ◽  
pp. 04009
Author(s):  
A. A. Korobov ◽  
R. R. Akhmetshin ◽  
A. N. Amirkhanov ◽  
A. V. Anisenkov ◽  
V. M. Aulchenko ◽  
...  

The cross section of the process e+e−→ π+π−π+π− has been measured using an integrated luminosity of 17 pb−1 collected with the CMD-3 detector in the center-of-mass energy range 650-1000 MeV. High-precision measurements of various hadronic cross sections are of great interest in relation with the problem of the muon anomalous magnetic moment g-2. This measurement can be also used to test the relation between the cross section of e+e−→ π+ π−π+ π− and the spectral function for the τ−→ π−π0π0π0 decay predicted by the conservation of vector current (CVC).


2005 ◽  
Vol 727 (1-2) ◽  
pp. 395-405 ◽  
Author(s):  
M. Ablikim ◽  
J.Z. Bai ◽  
Y. Ban ◽  
J.G. Bian ◽  
X. Cai ◽  
...  

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
◽  
A. M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Measurements of the differential cross sections of Z + jets and γ + jets production, and their ratio, are presented as a function of the boson transverse momentum. Measurements are also presented of the angular distribution between the Z boson and the closest jet. The analysis is based on pp collisions at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 35.9 fb−1 recorded by the CMS experiment at the LHC. The results, corrected for detector effects, are compared with various theoretical predictions. In general, the predictions at higher orders in perturbation theory show better agreement with the measurements. This work provides the first measurement of the ratio of the differential cross sections of Z + jets and γ + jets production at 13 TeV, as well as the first direct measurement of Z bosons emitted collinearly with a jet.


2009 ◽  
Vol 24 (02n03) ◽  
pp. 450-453
Author(s):  
◽  
T. SKORODKO ◽  
M. BASHKANOV ◽  
D. BOGOSLOWSKY ◽  
H. CALÉN ◽  
...  

The two-pion production in pp-collisions has been investigated in exclusive measurements from threshold up to Tp = 1.36 GeV . Total and differential cross sections have been obtained for the channels pnπ+π0, ppπ+π-, ppπ0π0 and also nnπ+π+. For intermediate incident energies Tp > 1 GeV , i.e. in the region, which is beyond the Roper excitation but at the onset of ΔΔ excitation the total ppπ0π0 cross section falls behind theoretical predictions by as much as an order of magnitude near 1.2 GeV, whereas the nnπ+π+ cross section is a factor of five larger than predicted. A model-unconstrained isospin decompostion of the cross section points to a significant contribution of an isospin 3/2 resonance other than the Δ(1232). As a possible candidate the Δ(1600) is discussed.


2018 ◽  
Vol 178 ◽  
pp. 04008
Author(s):  
X. Fang ◽  
W. P. Tan ◽  
M. Beard ◽  
R. J. deBoer ◽  
G. Gilardy ◽  
...  

The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.


2019 ◽  
Vol 212 ◽  
pp. 04006
Author(s):  
Evgeny Kozyrev ◽  
Evgeny Solodov ◽  
Vladimir Druzhinin

We report the results on the channels e+e−→ π+π−π0π0π0(η), e+e−→ π+π−η. Also we present the study of the two-photon process e+e−→ e+e−η' in the double-tag mode. The results for the form factor are compared with the predictions based on pQCD and VMD. The results are obtained by using the full data set of about 470 fb−1 collected by the BABAR experiment at the PEP-II e+e−collider at a center-of-mass energy of about 10.6 GeV.


2019 ◽  
Vol 79 (11) ◽  
Author(s):  
A. D. Bolognino ◽  
Francesco Giovanni Celiberto ◽  
M. Fucilla ◽  
D. Yu. Ivanov ◽  
A. Papa

AbstractThe inclusive hadroproduction of two heavy quarks, featuring a large separation in rapidity, is proposed as a novel probe channel of the Balitsky–Fadin–Kuraev–Lipatov (BFKL) approach. In a theoretical setup which includes full resummation of leading logarithms in the center-of-mass energy and partial resummation of the next-to-leading ones, predictions for the cross section and azimuthal coefficients are presented for kinematic configurations typical of current and possible future experimental analyses at the LHC.


2018 ◽  
Vol 182 ◽  
pp. 02052
Author(s):  
Asma Hadef

The Higgs boson was discovered on the 4th of July 2012 with a mass around 125 GeV by ATLAS and CMS experiments at LHC. Determining the Higgs properties (production and decay modes, couplings,...) is an important part of the high-energy physics programme in this decade. A search for the Higgs boson production in association with a top quark pair (tt̄H) at ATLAS [1] is summarized in this paper at an unexplored center-of-mass energy of 13 TeV, which could allow a first direct measurement of the top quark Yukawa coupling and could reveal new physics. The tt̄H analysis in ATLAS is divided into 3 channels according to the Higgs decay modes: H → Hadrons, H → Leptons and H → Photons. The best-fit value of the ratio of observed and Standard Model cross sections of tt̄H production process, using 2015-2016 data and combining all tt̄H final states, is 1:8±0:7, corresponds to 2:8σ (1:8σ) observed (expected) significance.


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