scholarly journals STUDY OF THE ELECTROMAGNETIC TRANSITIONS J/ψ → P l+l- AND PROBE DARK PHOTON

2012 ◽  
Vol 27 (38) ◽  
pp. 1250223 ◽  
Author(s):  
JINLIN FU ◽  
HAI-BO LI ◽  
XIAOSHUAI QIN ◽  
MAO-ZHI YANG
Keyword(s):  
Form Factor ◽  
Internal Conversion ◽  
Massive Particle ◽  
Lepton Pairs ◽  
Data Set ◽  
Decay Modes ◽  
Electromagnetic Structure ◽  
Dark Photon ◽  
The Standard Model ◽  
Shed Light

We study the electromagnetic Dalitz decay modes of J/ψ → P l+l- (P = π0, η or η′). In these decays, the lepton pairs are formed by internal conversion of an intermediate virtual photon with invariant mass ml+l-. Study of the effective-mass spectrum of the l+l- will shed light on the dynamic transition form factor [Formula: see text], which characterizes the electromagnetic structure arising at the vertex of the transition J/ψ to pseudoscalars. We also discuss the direct productions of a GeV scale vector U boson in these processes J/ψ → PU (U → l+l-). It is responsible for mediating a new U(1)d interaction, as recently exploited in the context of weakly interacting massive particle dark matter. In this paper, we firstly use the usual pole approximation for the form factor to estimate the decay rate of J/ψ → P l+l- in the Standard Model. Then the reach of searching for the dark photon is estimated. We suggest that these Dalitz decays can be used to search for the light U boson in the BESIII experiment with a huge J/ψ data set.

scholarly journals Dark Photon Searches at BESIII

2018 ◽  
Vol 46 ◽  
pp. 1860046 ◽  
Author(s):  
Dayong Wang
Keyword(s):  
Degrees Of Freedom ◽  
New Physics ◽  
Beyond The Standard Model ◽  
Gauge Bosons ◽  
Data Set ◽  
Decay Modes ◽  
Dark Photon ◽  
The Standard Model ◽  
New Type ◽  
Low Mass

Many models beyond the Standard Model, motivated by the recent astrophysical anomalies, predict a new type of weak-interacting degrees of freedom. Typical models include the possibility of the low-mass dark gauge bosons of a few GeV and thus making them accessible at the BESIII experiment running at the tau-charm region. The BESIII has recently searched such dark bosons in several decay modes using the high statistics data set collected at charmonium resonaces. This talk will summarize the recent BESIII results of these dark photon searches and related new physics studies.

scholarly journals Measurement of the Time-like Pion Transition Form Factor at BESIII

2019 ◽  
Vol 212 ◽  
pp. 04013
Author(s):  
Thomas Lenz ◽  
Achim Denig ◽  
Christoph Florian Redmer
Keyword(s):  
Form Factor ◽  
Magnetic Moment ◽  
Anomalous Magnetic Moment ◽  
Transition Form Factor ◽  
High Momentum ◽  
Transition Form ◽  
Model Calculations ◽  
The Standard Model ◽  
Important Input ◽  
Shed Light

The pion transition form factor is an important input to the dispersive approaches of the Standard Model calculations for the anomalous magnetic moment of the muon. We report the prospects of a first measurement at high momentum transfer in the time-like region performed at BESIII. The aim is to improve the uncertainty of the hadronic light-by-light calculations and to shed light on the BaBar-Belle puzzle in the space-like region.

scholarly journals Dark Photon Searches Using Displaced Vertices at Low Energye+e-Colliders

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Fabio Bossi
Keyword(s):  
Search Strategy ◽  
Massive Particle ◽  
Interaction Point ◽  
Dark Photon ◽  
Electron Positron ◽  
The Standard Model ◽  
Long Lifetime ◽  
Electron Positron Pair ◽  
Very High ◽  
Primary Interaction

The existence of a new, photon-like, massive particle, theγ′or dark photon, is postulated in several extensions of the Standard Model. These models are often advocated to explain some recent puzzling astrophysical observations, as well as to solve the so far unexplained deviation between the measured and calculated values of the muon anomaly. Dark photons can be produced ate+e-colliders both in continuum events and in vector meson transitions and can eventually decay into an electron-positron pair. For a proper choice of the parameters of the theory, aγ′can have a relatively long lifetime and can therefore be observed as ane+e-vertex well separated by the primary interaction point. This case is discussed in reference to very high luminositye+e-colliders either in construction or under study in several laboratories in the world. It is shown that a search strategy based on the detection of displaced vertices can be in principle very effective in covering a rather wide and to date unexplored region of the theoretical parameters space.

EXPRESS: How Does Bonus Payment Affect the Demand for Auto Loans and Their Delinquency?

2021 ◽  
pp. 002224372110092
Author(s):  
Zhenling Jiang ◽  
Dennis J. Zhang ◽  
Tat Chan
Keyword(s):  
Consumer Products ◽  
Data Set ◽  
Financial Decisions ◽  
Consumer Panel ◽  
Loan Demand ◽  
Bonus Payments ◽  
Base Salary ◽  
Long Term Impact ◽  
Shed Light

This paper studies how receiving a bonus changes the consumers’ demand for auto loans and the risk of future delinquency. Unlike traditional consumer products, auto loans have a long-term impact on consumers’ financial state because of the monthly payment obligation. Using a large consumer panel data set of credit and employment information, the authors find that receiving a bonus increases auto loan demand by 21 percent. These loans, however, are associated with higher risk, as the delinquency rate increases by 18.5 −31.4 percent depending on different measures. In contrast, an increase in consumers’ base salary will increase the demand for auto loans but not the delinquency. By comparing consumers with bonuses with those without bonuses, the authors find that bonus payments lead to both demand expansion and demand shifting on auto loans. The empirical findings help shed light on how consumers make financial decisions and have important implications for financial institutions on when demand for auto loans and the associated risk arise.

scholarly journals Astrophysical aspects of milli-charged dark matter in a Higgs–Stueckelberg model

2015 ◽  
Vol 30 (18) ◽  
pp. 1550089 ◽  
Author(s):  
A. L. dos Santos ◽  
D. Hadjimichef
Keyword(s):  
Dark Matter ◽  
Weakly Interacting Massive Particles ◽  
Dark Sector ◽  
Minimal Coupling ◽  
Astrophysical Application ◽  
Gauge Sector ◽  
Dark Photon ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Impact

An extension of the Standard Model (SM) is studied, in which two new vector bosons are introduced, a first boson Z' coupled to the SM by the usual minimal coupling, producing an enlarged gauge sector in the SM. The second boson A' field, in the dark sector of the model, remains massless and originates a dark photon γ'. A hybrid mixing scenario is considered based on a combined Higgs and Stueckelberg mechanisms. In a Compton-like process, a photon scattered by a weakly interacting massive particles (WIMP) is converted into a dark photon. This process is studied, in an astrophysical application obtaining an estimate of the impact on stellar cooling of white dwarfs and neutron stars.

scholarly journals Search for heavy neutral leptons in $$W^+\rightarrow \mu ^{+}\mu ^{\pm }\, \text {jet}$$ decays

2021 ◽  
Vol 81 (3) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  
Keyword(s):  
Mass Range ◽  
Lepton Number ◽  
Heavy Neutrino ◽  
Proton Collision ◽  
Final State ◽  
Data Set ◽  
Proton Proton ◽  
Upper Limits ◽  
The Standard Model ◽  
Proton Proton Collision

AbstractA search is performed for heavy neutrinos in the decay of a W boson into two muons and a jet. The data set corresponds to an integrated luminosity of approximately $$3.0\, \text {fb} ^{-1} $$ 3.0 fb - 1 of proton–proton collision data at centre-of-mass energies of 7 and $$8\, \text {TeV} $$ 8 TeV collected with the LHCb experiment. Both same-sign and opposite-sign muons in the final state are considered. Data are found to be consistent with the expected background. Upper limits on the coupling of a heavy neutrino with the Standard Model neutrino are set at $$95\%$$ 95 % confidence level in the heavy-neutrino mass range from 5 to $$50\, \text {GeV/}c^2 $$ 50 GeV/ c 2 . These are of the order of $$10^{-3}$$ 10 - 3 for lepton-number-conserving decays and of the order of $$10^{-4}$$ 10 - 4 for lepton-number-violating heavy-neutrino decays.

scholarly journals Genome-wide analyses reveal clustering in Cannabis cultivars: the ancient domestication trilogy of a panacea

2015 ◽  
Author(s):  
Philippe Henry
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
Open Access ◽  
Nucleotide Polymorphisms ◽  
Data Set ◽  
Single Nucleotide ◽  
Genome Wide ◽  
Access Data ◽  
Diagnostic Snps ◽  
Shed Light

In the present research, I used an open access data set (Medicinal Genomics) consisting of nearly 200'000 genome-wide single nucleotide polymorphisms (SNPs) typed in 28 cannabis accessions to shed light on the plant's underlying genetic structure. Genome-wide loadings were used to sequentially cull less informative markers. The process involved reducing the number of SNPs to 100K, 10K, 1K, 100 until I identified a set of 42 highly informative SNPs that I present here. The two first principal components, encompass over 3/4 of the genetic variation present in the dataset (PCA1 = 48.6%, PCA2= 26.3%). This set of diagnostic SNPs is then used to identify clusters into which cannabis accession segregate. I identified three clear and consistent clusters; reflective of the ancient domestication trilogy of the genus Cannabis.

Change and continuity in Hurstville’s Chinese restaurants

2021 ◽  
Author(s):  
Samantha Zhan Xu ◽  
Wei Wang
Keyword(s):  
Linguistic Landscape ◽  
Data Set ◽  
Landscape Studies ◽  
Chinese Restaurant ◽  
Temporal And Spatial ◽  
Restaurant Owners ◽  
Depth Interviews ◽  
Shed Light ◽  
Sydney Australia

Abstract This paper investigates the Linguistic Landscape of Chinese restaurants in Hurstville, a Chinese-concentrated suburb in Sydney, Australia. It draws on Blommaert and Maly’s (2016) Ethnographic Linguistic Landscape Analysis (ELLA) and Scollon and Scollon’s geosemiotics (2003). Our data set consists of photographs, Google Street View archives, and ethnographic fieldwork, in particular in-depth interviews with restaurant owners. This paper adopts a diachronic perspective to compare the restaurant scape between 2009 and 2019 and presents an ELLA case study of a long-standing Chinese restaurant. It aims to unveil the temporal and spatial relationships between signs, agents, and place, that demonstrate how a social and historical perspective in Linguistic Landscape studies of diasporic communities can shed light on the changes in the broader social context.

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 Proposal to Search for a Dark Photon in Positron on Target Collisions at DAΦNE Linac

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Mauro Raggi ◽  
Venelin Kozhuharov
Keyword(s):  
Interaction Strength ◽  
Positron Beam ◽  
Mass Region ◽  
Experimental Setup ◽  
Dark Photon ◽  
Analysis Technique ◽  
The Standard Model ◽  
Vector Bosons ◽  
Target Experiment ◽  
One Year

Photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The present paper proposes a search for such particles in thee+e-→Uγprocess in a positron-on-target experiment, exploiting the positron beam of the DAΦNE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to ~10−6is achievable, in the mass region from 2.5 MeV<MU<20 MeV. The proposed experimental setup and the analysis technique are discussed.

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