scholarly journals Production Mechanism of the Charmed Baryon Λc+

Symmetry ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 5
Author(s):  
Weiping Wang ◽  
Xiaorong Zhou ◽  
Rinaldo Baldini Ferroli ◽  
Guangshun Huang
Keyword(s):  
Cross Section ◽  
Production Cross ◽  
Center Of Mass ◽  
Polar Angle ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Production Mechanism ◽  
Charmed Baryon ◽  
Electron Positron ◽  
State Radiation

As the lightest charmed baryon, precision measurement of the pair production cross section of provides unprecedented experimental information for the investigation of baryon production mechanism. In addition, the extraction of the polar angle distributions of the outgoing in the annihilation of the electron–positron help to determine its electromagnetic form factors, which is currently the unique key to access the internal structure of the baryons. In this article, the measurement of process via the initial state radiation technique at Belle detector and direct electron–positron annihilation at BESIII with discrete center-of-mass energies near threshold are briefly reviewed. In addition, the electromagnetic form factor ratios of measured by BESIII are also investigated. A few theoretical models that parameterize the center-of-mass energy dependence of the cross section and electromagnetic form factors of baryon are introduced and the contributions of data to them are discussed.

scholarly journals Hadron Form Factors at BESIII

2018 ◽  
Vol 46 ◽  
pp. 1860027
Author(s):  
Zhaoxia Meng
Keyword(s):  
Cross Section ◽  
Center Of Mass ◽  
Polar Angle ◽  
Form Factors ◽  
Angle Distribution ◽  
Initial State ◽  
Fundamental Information ◽  
Born Cross Section ◽  
Effective Form ◽  
State Radiation

Form factors of hadron provide fundamental information about its structure and dynamics. They constitute a rigorous test of non-perturbative QCD as well as of phenomenological models. Based on data samples collected with BESIII detector at BEPCII collider, born cross section of [Formula: see text] and proton effective form factors are measured at 12 center-of-mass energies between 2.2324 and 3.671 GeV. The ratio [Formula: see text]s are extracted by fitting polar angle distribution of proton for data samples with large statistics. For data between 3.773 and 4.6 GeV, we use initial state radiation (ISR) method to study [Formula: see text] by tagged or un-tagged ISR photon, where the pair cross section, effective form factors and [Formula: see text]s are obtained from proton pair threshold to about 3 GeV. For [Formula: see text] and [Formula: see text], the pair cross section and [Formula: see text] form factors are measured near threshold. With data scanned in 2015 from 2-3.08 GeV, charged Kaon pair cross section and form factors are measured at 21 center-of-mass energies.

scholarly journals Measurement of hadronic form factors at BESIII

2018 ◽  
Vol 172 ◽  
pp. 03002
Author(s):  
Haiming HU
Keyword(s):  
Form Factor ◽  
Cross Section ◽  
Center Of Mass ◽  
Polar Angle ◽  
Form Factors ◽  
Pion Form Factor ◽  
Angle Distribution ◽  
Data Set ◽  
Center Of Mass Energy ◽  
The Cross

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.

scholarly journals MEASUREMENT OF THE PROTON ELECTROMAGNETIC FORM FACTORS AT BABAR

2014 ◽  
Vol 35 ◽  
pp. 1460425
Author(s):  
V. P. DRUZHININ ◽  
Keyword(s):  
Center Of Mass ◽  
Form Factors ◽  
Mass Range ◽  
Initial State Radiation ◽  
Electromagnetic Form Factors ◽  
Initial State ◽  
State Radiation ◽  
Radiation Technique ◽  
Babar Detector ◽  
Integrated Luminosity

The process [Formula: see text] has been studied in the [Formula: see text] mass range from threshold to 6.5 GeV/c2 using the initial-state-radiation technique with both detected and undetected photon. The analysis is based on 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider at e+e- center-of-mass energies near 10.6 GeV.

scholarly journals Experimental Review of ΛΛ¯ Production

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 144
Author(s):  
Xiaorong Zhou ◽  
Liang Yan ◽  
Rinaldo Baldini Ferroli ◽  
Guangshun Huang
Keyword(s):  
Positron Annihilation ◽  
Cross Section ◽  
Production Cross ◽  
High Energy ◽  
Threshold Region ◽  
Initial State ◽  
Precision Data ◽  
Electron Positron Annihilation ◽  
Electron Positron ◽  
State Radiation

Exclusive hyperon-antihyperon production provides a unique insight for understanding of the intrinsic dynamics when strangeness is involved. In this paper, we review the results of ΛΛ¯ production via different reactions from various experiments, e.g., via p¯p annihilation from the LEAR experiment PS185, via electron-positron annihilation using the energy scan method at the CLEO-c and BESIII experiments and the initial-state-radiation approach utilized at the BaBar experiment. The production cross section of ΛΛ¯ near the threshold is sensitive to QCD based prediction. Experimental high precision data for p¯p→Λ¯Λ close to the threshold region is obtained. The cross section of e+e−→ΛΛ¯ is measured from its production threshold to high energy. A non-zero cross section for e+e−→ΛΛ¯ near threshold is observed at BaBar and BESIII, which is in disagreement with the pQCD prediction. However, more precise data is needed to confirm this observation. Future experiments, utilizing p¯p reaction such as PANDA experiment or electron-positron annihilation such as the BESIII and BelleII experiments, are needed to extend the experimental data and to understand the ΛΛ¯ production.

scholarly journals BESIII results on time-like baryon form factors

2019 ◽  
Vol 218 ◽  
pp. 04002
Author(s):  
Alaa Dbeyssi
Keyword(s):  
Form Factor ◽  
Center Of Mass ◽  
Form Factors ◽  
Initial State Radiation ◽  
Proton Form Factor ◽  
Electromagnetic Form Factors ◽  
Initial State ◽  
Data Set ◽  
Preliminary Results ◽  
State Radiation

This contribution reports on the recent measurements of baryon electromagnetic form factors at the BESIII experiment in Beijing. The Beijing e+e − collider BEPCII is a double-ring symmetric collider running at $ \sqrt s $ between 2.0 and 4.6 GeV. Baryon electromagnetic form factors can be measured at BESIII in direct e+e−-annihilation and in initial state radiation processes. Based on the data collected by the BESIII detector at 12 center of mass energies between 2.23 and 3.67 GeV, the measured $ \mathop e\nolimits^ + \mathop e\nolimits^ - \to \mathop p\limits^ - p $ cross section and the time-like proton form factor are presented. Preliminary results from the analysis of the initial state radiation process $ \mathop e\nolimits^ + \mathop e\nolimits^ - \to \mathop p\limits^ - p\gamma $ using a data set of 7.408 fb−1 collected at center of mass energies between 3.773 and 4.6 GeV, are also shown. The cross sections for $ \mathop e\nolimits^ + \mathop e\nolimits^ - \to \mathop {\mathop \Lambda \nolimits_c^ - }\limits^ - \mathop \Lambda \nolimits_c^ + $ and $ \mathop e\nolimits^ + \mathop e\nolimits^ - \to \mathop \Lambda \limits^ - \Lambda $ are measured near threshold with unprecedented precision. Preliminary results on the first measurement of the ^c form factor ratio |GE|/|GM| are also given. Ongoing analysis based on the high luminosity energy scan from 2015 and from radiative return at different $ \sqrt s $ are also described.

scholarly journals Collinear expansion for color singlet cross sections

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Gluon Fusion ◽  
Building Blocks ◽  
Color Singlet ◽  
Final State ◽  
Beam Function ◽  
Kinematic Limit ◽  
State Radiation

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

scholarly journals Hadronic form factors and theJ/ψsecondary production cross section: An update

2005 ◽  
Vol 72 (2) ◽  
Author(s):  
F. Carvalho ◽  
F. O. Durães ◽  
F. S. Navarra ◽  
M. Nielsen
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Production Cross ◽  
Form Factors

scholarly journals Search for a heavy Higgs boson decaying into two lighter Higgs bosons in the ττbb final state at 13 TeV

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
A. Tumasyan ◽  
W. Adam ◽  
J. W. Andrejkovic ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Higgs Boson ◽  
Cross Section ◽  
Production Cross Section ◽  
Production Cross ◽  
Branching Fractions ◽  
Center Of Mass ◽  
Final State ◽  
Signal Process ◽  
Center Of Mass Energy ◽  
Heavy Higgs Boson

Abstract A search for a heavy Higgs boson H decaying into the observed Higgs boson h with a mass of 125 GeV and another Higgs boson hS is presented. The h and hS bosons are required to decay into a pair of tau leptons and a pair of b quarks, respectively. The search uses a sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 137 fb−1. Mass ranges of 240–3000 GeV for mH and 60–2800 GeV for $$ {m}_{{\mathrm{h}}_{\mathrm{S}}} $$ m h S are explored in the search. No signal has been observed. Model independent 95% confidence level upper limits on the product of the production cross section and the branching fractions of the signal process are set with a sensitivity ranging from 125 fb (for mH = 240 GeV) to 2.7 fb (for mH = 1000 GeV). These limits are compared to maximally allowed products of the production cross section and the branching fractions of the signal process in the next-to-minimal supersymmetric extension of the standard model.

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