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Inclusive transverse momentum spectra of primary charged particles in Pb–Pb collisions at √sNN=2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0–5% and 70–80% of the hadronic Pb–Pb cross section. The measured charged particle spectra in |η|<0.8 and 0.3<pT<20 GeV/c are compared to the expectation in pp collisions at the same sNN, scaled by the number of underlying nucleon–nucleon collisions. The comparison is expressed in terms of the nuclear modification factor RAA. The result indicates only weak medium effects (RAA≈0.7) in peripheral collisions. In central collisions, RAA reaches a minimum of about 0.14 at pT=6–7 GeV/c and increases significantly at larger pT. The measured suppression of high-pT particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb–Pb collisions at the LHC.
Rapidity and transverse momentum dependence of inclusive J/ψ production in pp collisions at √s=7 TeV
(2011)
The ALICE experiment at the LHC has studied inclusive J/ψ production at central and forward rapidities in pp collisions at √s=7 TeV. In this Letter, we report on the first results obtained detecting the J/ψ through the dilepton decay into e+e− and μ+μ− pairs in the rapidity ranges |y|<0.9 and 2.5<y<4, respectively, and with acceptance down to zero pT. In the dielectron channel the analysis was carried out on a data sample corresponding to an integrated luminosity Lint=5.6 nb−1 and the number of signal events is NJ/ψ=352±32(stat.)±28(syst.); the corresponding figures in the dimuon channel are Lint=15.6 nb−1 and NJ/ψ=1924±77(stat.)±144(syst.). The measured production cross sections are σJ/ψ(|y|<0.9)=10.7±1.0(stat.)±1.6(syst.)−2.3+1.6(syst.pol.)μb and σJ/ψ(2.5<y<4)=6.31±0.25(stat.)±0.76(syst.)−1.96+0.95(syst.pol.)μb. The differential cross sections, in transverse momentum and rapidity, of the J/ψ were also measured.
Measurements of charged-particle production in pp, p−Pb, and Pb−Pb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum (ptrigT) in the range 8<ptrigT<15 GeV/c. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, RT=NTch/⟨NTch⟩, is used to group events according to their UE activity, where NTch is the charged-particle multiplicity per event in the transverse region and ⟨NTch⟩ is the mean value over the whole analysed sample. The energy dependence of the RT distributions in pp collisions at s√=2.76, 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle pT spectra as a function of RT in the three azimuthal regions in pp, p−Pb, and Pb−Pb collisions at sNN−−−√=5.02 TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and p−Pb).
The Chinese species of the genus Chinoperla Zwick, 1980 are reviewed. One species from Hainan is described as new to science: C. changjiangensis sp. nov. Chinoperla gorohovi Sivec & Stark, 2010 is reported from China for the first time, with a redescripion and color images of the male, and the first description of the female and egg. Chinoperla nigrifrons (Banks, 1939) is redescribed and illustrated, synonymy of C. furcomacula (Wu, 1973) is confirmed. Taxonomic relationships within the studied species are discussed. A provisional key to the six known species of Chinoperla for China is presented.
In BRST-quantised Yang-Mills theory the existence of BRST symmetry imposes significant constraints on the analytic structure of the continuum theory. In particular, the presence of this symmetry in the non-perturbative regime implies that any on-shell state with vanishing norm must have an associated partner state with identical mass, but negative inner product. In this work we demonstrate that for quantum chromodynamics (QCD) this constraint gives rise to an interconnection between the ghost and gluon spectra, and in doing so provides a non-trivial test of whether BRST symmetry is realised non-perturbatively. By analysing infrared lattice data for the minimal Landau gauge ghost propagator in pure SU(3) Yang-Mills theory, and comparing this with previous results for the gluon propagator, we show that this interconnection is violated, and hence conclude that continuum and current lattice formulations of Yang-Mills theory in Landau gauge represent two distinct realisations of the theory.
US data and new stockholding data from fifteen European countries and China exhibit a common pattern: stockholding shares increase in household income and wealth. Yet, there is a multitude of numbers to match through models. Using a single utility function across households (parsimony), we suggest a strategy for fitting stockholding numbers, while replicating that saving rates increase in wealth, too. The key is introducing subsistence consumption to an Epstein-Zin-Weil utility function, creating endogenous risk-aversion differences across rich and poor. A closed-form solution for the model with insurable labor-income risk serves as calibration guide for numerical simulations with uninsurable labor-income risk.
We compare the cost effectiveness of two pronatalist policies:
(a) child allowances; and
(b) daycare subsidies.
We pay special attention to estimating how intended fertility (fertility before children are born) responds to these policies. We use two evaluation tools:
(i) a dynamic model on fertility, labor supply, outsourced childcare time, parental time, asset accumulation and consumption; and
(ii) randomized vignette-survey policy experiments.
We implement both tools in the United States and Germany, finding consistent evidence that daycare subsidies are more cost effective. Nevertheless, the required public expenditure to increase fertility to the replacement level might be viewed as prohibitively high.
Following the introduction of the one-child policy in China, the capital-labor (K/L) ratio of China increased relative to that of India, and, simultaneously, FDI inflows relative to GDP for China versus India declined. These observations are explained in the context of a simple neoclassical OLG paradigm. The adjustment mechanism works as follows: the reduction in the growth rate of the (urban) labor force due to the one-child policy permanently increases the capital per worker inherited from the previous generation. The resulting increase in China's (domestic K)/L thus "crowds out" the need for FDI in China relative to India. Our paper is a contribution to the nascent literature exploring demographic transitions and their effects on FDI flows.
After the Lehman-Brothers collapse, the stock index has exceeded its pre-Lehman-Brothers peak by 36% in real terms. Seemingly, markets have been demanding more stocks instead of bonds. Yet, instead of observing higher bond rates, paradoxically, bond rates have been persistently negative after the Lehman-Brothers collapse. To explain this paradox, we suggest that, in the post-Lehman-Brothers period, investors changed their perceptions on disasters, thinking that disasters occur once every 30 years on average, instead of disasters occurring once every 60 years. In our asset-pricing calibration exercise, this rise in perceived market fragility alone can explain the drop in both bond rates and price-dividend ratios observed after the Lehman-Brothers collapse, which indicates that markets mostly demanded bonds instead of stocks.
Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p–Pb collisions at a nucleon–nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 < pT,assoc < pT,trig < 5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |η| < 0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p–Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton–parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p–Pb collisions. Further, the number scales only in the intermediate multiplicity region with the number of binary nucleon–nucleon collisions estimated with a Glauber Monte-Carlo simulation.
In fifteen European countries, China, and the US, stocks and business equity as a share of total household assets are represented by an increasing and convex function of income/wealth. A parsimonious model fitted to the data shows why background labor- income risk can explain much of this risk-taking pattern. Uncontrollable labor-income risk stresses middle-income households more because labor income is a larger fraction of their total lifetime resources compared with the rich. In response, middle-income households re-duce (controllable) financial risk. Richer households, having less pressure, can afford more risk-taking. The poor take low risk because they avoid jeopardizing their subsistence consumption.
Three new species of pseudoscorpion, Allochthonius lini sp. nov. (Xiaoguoquan Cave) and Selachochthonius yinae sp. nov. (Xiao Cave) from Yunnan Province, Allochthonius xuae sp. nov. (Yelaoda Cave) from Guizhou Province, are described and illustrated. An identification key is provided for all known Chinese representatives of the family Pseudotyrannochthoniidae.
Business practitioners increasingly use Artificial Intelligence (AI) applications to assist customers in making decisions due to their higher prediction quality. Yet, customers are frequently reluctant to rely on advice generated from machines, especially when their decision is at stake. Our study proposes a solution, which is to bring a human expert in the loop of machine advice. We empirically test whether customers are more accepting expert-AI collaborative advice than expert or AI advice.
The pricing of an ambiguous asset, whose cash flow stream is uncertain, may be affected by three factors: the belief regarding the realization likelihood of cash flows, the subjective attitude towards risk, and the attitude towards ambiguity. While previous literature looks at the total price discount under ambiguity, this paper investigates with laboratory experiments how much effect each factor can induce. We apply both non-parametric and parametric methods to cleanly separate the belief effects, the risk premiums, and the ambiguity premiums from each other. Both methods lead to similar results: Overall, subjects have substantial ambiguity aversion, and ambiguity premiums account for the largest price deviation component when the degree of ambiguity is high. As information accumulates, ambiguity premiums decrease. We also find that beliefs do influence prices under ambiguity. This is not because beliefs are biased towards either good or bad scenarios per se, but because subjects display sticky belief updating as new information becomes available. The clear separation performed in this paper between belief and attitude also enables a more accurate estimation of the parameter of ambiguity aversion compared to previous studies, since the effect of beliefs is partialled out. Overall, we find empirically that both factors, belief and attitude towards ambiguity, are important factors in pricing under ambiguity.
Twenty previously known species of Fissocantharis Pic, 1921 and Micropodabrus Pic, 1920 from Taiwan are illustrated and described with the genitalia of both sexes and or abdominal sternite VIII of female. The following reconfirmed combinations are proposed, Micropodabrus chujoi (Wittmer, 1972), M. mucronata (Wittmer, 1979), M. multicostata (Wittmer, 1982) and M. nodicornis (Wittmer, 1982), which were all originally described in Kandyosilis Pic, 1929. Two new species are described, Fissocantharis nigriceps Y. Yang & Okushima sp. nov. and Micropodabrus brunneipennis Y. Yang & Okushima sp. nov., which are provided with the illustrations of aedeagus and photos of male habitus.
This paper sets up an experimental asset market in the laboratory to investigate the effects of ambiguity on price formation and trading behavior in financial markets. The obtained trading data is used to analyze the effect of ambiguity on various market outcomes (the price level, volatility, trading activity, market liquidity, and the degree of speculative trading) and to test the quality of popular empirical market-based measures for the degree of ambiguity. We find that ambiguity decreases market prices and trading activity; ambiguity leads to lower market liquidity through wider bid-ask spreads; and ambiguity leads to less speculative trading. We also find that popular market-based measures of ambiguity used in the empirical literature do not seem to correctly capture the true degree of ambiguity.
Twenty species of the genus Chilocorus Leach, 1815 currently known from China are recorded, including two new species described here: C. nigricaeruleus Li & Wang sp. nov. and C. strenotubus Li & Wang sp. nov. Diagnoses and detailed descriptions of the new species are given. Each species is illustrated in detail, including genitalia. Distribution maps, a key to the Chinese species and a world checklist of Chilocorus are given.
The planthopper genus Arcofaciella Fennah, 1956 (Hemiptera: Fulgoromorpha: Delphacidae) is reviewed. Four species are recognized, of which A. obflexa Guo & Liang, 2005 and A. verrucosa Fennah, 1956 are redescribed, and one new species, A. indiana sp. nov., is described. Habitus photos for adults and illustrations of male genitalia (excluding A. penangensis (Muir, 1919)) are given. A key for identifying the species of Arcofaciella is also provided.