Methods for a blind analysis of isobar data collected by the STAR collaboration

In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.

Effect of dietary near ideal amino acid profile on heat production of lactating sows exposed to thermal neutral and heat stress conditions

Background:Reduced protein diet manifested potential to mitigate heat production based on the concept of ideal amino acid profile.The hypothesis of this study was that lactating sows fed a low crude protein(LCP)diet with supplemental amino acid produce less heat compared to those fed a high crude protein(HCP)diet under both thermal neutral(TN)and heat stress(HS)conditions.Methods:Thirty-two lactating sows were allotted to HCP(193 g CP/kg)and LCP(140 g CP/kg)diets under thermal neutral(TN,21±1.5°C)or cycling heat stress(HS,32±1.5°C daytime and 24±1.5°C nighttime)conditions.Diets contained 0.90%SID lysine and 10.8 MJ/kg net energy.Positive pressure indirect calorimeters were used to measure gas exchange in individual sows with litters,and individual piglets on days 4,8,14 and 18.Sow and litter weights were recorded on days 1,10 and 21.Results:Sow total heat production(THP)was calculated by subtracting litter THP from sow+litter THP based on BW0.75.Sow BW and body protein(BP)loss was greater for LCP diet compared to HCP diet in peak lactation(P<0.05 and P<0.01,respectively)and throughout the entire lactation period(P<0.05 and P=0.056,respectively)under HS conditions.Heat-stressed sows fed HCP diet had higher(P<0.05)rectal temperature at 13:00(P<0.05)and 19:00(P<0.01),and higher respiration rate at 07:00(P<0.05),13:00(P<0.05)and 19:00(P<0.05)compared to TN sows fed HCP diet.In sows fed LCP diet,those under HS tended to have higher(P=0.098)rectal temperature at 13:00 and had higher(P<0.05)respiration rate at 07:00,13:00 and 19:00 compared to TN sows.The relationship between daily THP and days in lactation of sows fed LCP diet was quadratic(P<0.05),with an ascending trend until day 14 and a descending trend from days 14 to 18.Sows fed LCP diet had lower daily THP at day 18(P<0.001)compared to those fed the HCP diet under HS conditions.Conclusion:Reduction in THP in sows fed LCP diet was largely associated with THP on day 18 of lactation under HS conditions.Feeding LCP diets alleviated the increased body temperature in sows under HS conditions throughout lactation,which was accompanied by a reduction in respiration rate.Total heat production is associated with days in lactation,in particular under HS conditions with THP appearing to peak between days 14 and 18.

Spectral and Timing Analysis of the Black Hole Transient MAXI J1631–479 During its 2019 Outburst Observed with Insight-HXMT

We report spectral and timing analysis of the black hole transient MAXI J1631–479 during the hard intermediate state of its 2019 outburst from the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)observations.We find that the energy dependence of the type-C quasi-periodic oscillation(QPO)frequency evolves with time:during the initial rise of a small flare(~MJD 58526.0-58527.1),the QPO frequency increases with increasing energy from~1 to~100 ke V,and then the frequency remains constant after MJD 58527.1.We discover a possible new phenomenon of Fe line’s QPO frequency jump that has never been observed for other black hole transients:during the small flare,the QPO frequency around the Fe line energy is higher than any other energy band,with the frequency difference Δf=0.25±0.08 Hz between 5.5–7.5 ke V and other energy bands.The spectral analysis shows that the evolution of QPOs is related to the equivalent width of the narrow Fe line,and its equivalent width increases during this small flare.We propose that the QPO frequency difference results from the differential precession of a vertically extended jet,and the higher QPO frequency of Fe line could be caused by the layered jet when the jet scale increases.At the same time,the evolution of QPOs is related to the accretion rate,while the energy dependence of QPOs supports the existence of deceleration in the vertically distributed jet.

Search for the doubly heavy baryon Ξ_(bc)^(+)→ decaying to J/ψΞ_(c)^(+)

A first search for the Ξ_(bc)^(+)J/ψΞ_(c)^(+) decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the Ξ+bc baryon production cross-section times the branching fraction relative to that of the B+c→J/ψD+s decay at centre-of-mass energies of 8 and 13 TeV, in the Ξ+bc and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV/c, respectively. Upper limits are presented as a function of the Ξ+bc mass and lifetime.

Search for the rare decays W^(+)→D_(s)^(+)γ and Z→D^(0)γ at LHCb

A search for the rare decays W^(+)→D_(s)^(+)γ and Z→D0γis performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV,corresponding to an integrated luminosity of 2.0fb−1.No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W^(+)→D_(s)^(+)γ and Z→μ+μ−decays as normalization channels.The upper limits are 6.5×10^(−4) and 2.1×10^(−3) at 95% confidence level for the W^(+)→D_(s)^(+)γ and Z→D^(0)γ decay modes,respectively.This is the first reported search for the Z→D^(0)γ decay,while the upper limit on the W+→D+sγbranching fraction improves upon the previous best limit.

Measurements of the center-of-mass energies of e^(+)e^(-)collisions at BESIII

During the 2016-17 and 2018-19 running periods,the BESIII experiment collected 7.5 fb of e^(+)e^(-)collision data at center-of-mass energies ranging from 4.13 to 4.44 GeV.These data samples are primarily used for the study of excited charmonium and charmoniumlike states.By analyzing the di-muon process e^(+)e^(-)→(γISR=FSR)μ^(+)μ^(-),we measure the center-of-mass energies of the data samples with a precision of 0.6 MeV.Through a run-by-run study,we find that the center-of-mass energies were stable throughout most of the data-collection period.

Measurements of dihadron correlations relative to the event plane in Au+Au collisions at√^(S)NN=200 GeV

Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with extens-ive systematic studies of the dihadron correlations as a function ofФ_(s),trigger and associated particle pT,and the pseudo-rapidity range△_(η),should provide stringent inputs to help understand the underlying physics mechanisms of jet-medium interactions in high energy nuclear collisions.

Study of BESIII trigger efficiencies with the 2018 J/ψ data

Using a dedicated data sample taken in 2018 on the J/ψpeak,we perform a detailed study of the trigger efficiencies of the BESIII detector.The efficiencies are determined from three representative physics processes,namely Bhabha scattering,dimuon production and generic hadronic events with charged particles.The combined efficiency of all active triggers approaches 100%in most cases,with uncertainties small enough not to affect most physics analyses.

Evidence of a J/ψΛstructure and observation of excited■^(-)states in the■b^(-)→J/ψΛK^(-) decay

First evidence of a structure in the J/ψΛinvariant mass distribution is obtained from an amplitude analysis of■b^(-)J/ψΛK^(-)decays.The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1r including systematic uncertainties and lookelsewhere effect.Its mass and width are determined to be 4458:8±2:9t4:7-1:1 MeV and 17:3±6:5t8:0-5:7 MeV,respectively,where the quoted uncertainties are statistical and systematic.The structure is also consistent with being due to two resonances.In addition,the narrow excited■^(-)states,N■(1690)and■(1820),are seen for the first time in a■b^(-)decay,and their masses and widths are measured with improved precision.The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb^(-1),collected with the LHCb experiment at centre-of-mass energies of 7,8 and 13 TeV.

Search for the doubly charmed baryon ■

A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.

Forging strength-ductility unity in a high entropy steel

Fe_(72.4)Co_(13.9)Cr_(10.4)Mn_(2.7)B_(0.34)high entropy steel was prepared by magnetron sputtering.The alloy exhibits a high yield strength of 2.92±0.36 GPa while achieving appreciable plasticity of 13.7±1.9%at the ultimate compressive strength(3.37±0.36 GPa).The distribution of iron and chromium shows an un-usual,characteristic spinodal-like pattern at the nanometer scale,where compositions of Fe and Cr show strong anticorrelation and vary by as much as 20 at.%.The high strength is largely attributable to the compositional modulations,combined with fine grains with body-centered cubic(BCC)crystal structure,as well as grain boundary segregation of interstitial boron.The impressive plasticity is accommodated by the formation and operation of multiplanar,multicharacter dislocation slips,mediated by coherent in-terfaces,and controlled by shear bandings.The excellent strength-ductility combination is thus enabled by a range of distinctive strengthening mechanisms,rendering the new alloy a potential candidate for safety-critical,load-bearing structural applications.

Measurement of Ξcc++ production in pp collisions at s1/2=13 TeV

The production of ■baryons in proton-proton collisions at a centre-of-mass energy of √s = 13 TeV is measured in the transverse-momentum range 4<pT<15GeV/c and the rapidity range2.0<y<4.5.The data used in this measurement correspond to an integrated luminosity of 1.7fb^-1,recorded by the LHCb experiment during 2016.The ratio of the ■ production cross-section times the branching fraction of the■→∧^+cK^-π^+ π^+decay relative to the prompt ∧^+c production cross-section is found to be(2.22±0.27±0.29)×10^-4,assuming the central value of the measured lifetime,where the first uncertainty is statistical and the second systematic.

Measurement of away-side broadening with self-subtraction of flow in Au+Au collisions at √sNN=200 GeV

High transverse momentum(pT)particle production is suppressed owing to the parton(jet)energy loss in the hot dense medium created in relativistic heavy-ion collisions.Redistribution of energy at low-to-modest pT has been difficult to measure,owing to large anisotropic backgrounds.We report a data-driven method for background evaluation and subtraction,exploiting the away-side pseudorapidity gaps,to measure the jetlike correlation shape in Au+Au collisions at √sNN=200 GeV in the STAR experiment.The correlation shapes,for trigger particles pT>3GeV/c and various associated particle pT ranges within 0.5<pT<10GeV/c,are consistent with Gaussians,and their widths increase with centrality.The results indicate jet broadening in the medium created in central heavy-ion collisions.

Selection of micro-fabrication techniques on stainless steel sheet for skin friction

This review gives a concise introduction to the state-of-art techniques used for surface texturing, e.g., wet etching, plasma etching, laser surface texturing (LST), 3D printing, etc. In order to fabricate deterministic textures with the desired geometric structures and scales, the innovative texturing technologies are developed and extended. Such texturing technology is an emerging frontier with revolutionary impact in industrial and scientific fields. With the help of the latest fabrication technologies, surface textures are scaling down and more complex deterministic patterns may be fabricated with desired functions, e.g., lotus effect (hydrophobic), gecko feet (adhesive), haptic tactile, etc. The objective of this review is to explore the surface texturing technology and its contributions to the applications.

Search for the doubly heavy baryons Ω^(0)_(bc) and E^(0)_(bc) decaying to Λ^(+)_(c)π^(-) and E^(+)_(c)π^(-)

The first search for the doubly heavyΩ^(0)_(bc)baryon and a search for the E^(0)_(bc)baryon are performed using pp collision data collected via the LHCb experiment from 2016 to 2018 at a centre-of-mass energy of 13 TeV,corresponding to an integrated luminosity of 5.2 fb^(-1).The baryons are reconstructed via their decays to Λ^(+)_(c)π^(-)and E^(+)_(c)π^(-).No significant excess is fbund for invariant masses between 6700 and 7300 MeV/c^(2),in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 MeV/c.Upper limits are set on the ratio of the Ω^(0)_(bc)and E^(0)_(bc)production cross-section times the branching fraction to Λ^(+)_(c)π^(-)(E^(+)_(c)π^(-))relative to that of the Λ^(0)_(b)(E^(0)_(b))baryon,for different lifetime hypotheses,at 95%confidence level.The upper limits range from 0.5 x 10^(-4)to 2.5 x 10^(-4)for theΩ^(0)_(bc)→Λ^(+)_(c)π^(-)(E^(0)_(bc)→Λ^(+)_(c)π^(-))decay,and from 1.4x 10^(-3)to 6.9 x 10^(-3)for theΩ^(0)_(bc)→E^(+)_(c)π^(-)(E^(0)_(bc)→E^(+)_(c)π^(-))decay,depending on the considered mass and lifetime of theΩ^(0)_(bc)(E^(0)_(bc))baryon.

Ω and φ in Au + Au collisions at (s_(NN))^(1/2)= 200 and 11.5 GeV from a multiphase transport model

Within the framework of a multiphase transport model, we study the production and properties of Ω andφ in Au ＋ Au collisions with a new set of parameters for （s（NN））^（1/2）= 200 GeV and with the original set of parameters for （s（NN））^（1/2）= 11.5 GeV. The AMPT model with string melting provides a reasonable description at （s（NN））^（1/2）= 200 GeV,while the default AMPT model describes the data well at （s（NN））^（1/2）= 11.5 GeV. This indicates that the system created at top RHIC energy is dominated by partonic interactions, while hadronic interactions become important at lower beam energy, such as （s（NN））^（1/2）= 11.5 GeV. The comparison of N（Ω^＋＋Ω^-）/[2N（φ）] ratio between data and calculations further supports the argument. Our calculations can generally describe the data of nuclear modification factor as well as elliptic flow.

Number of J/ψ events at BESIII

Using inclusive decays of J/ψ aprecise determination of the number of J/ψ events collected with the BESIII detector was performed.For the two data sets taken in 2009 and 2012,the numbers of J/ψ events were recalculated to be(224.0±1.3)×10^(6) and(1088.5±4.4)×10^(6),respectively;these numbers are in good agreement with the previous measurements. For the J/ψ sample taken in 2017-2019,the number of events was determined to be(8774.0±39.4)×10^(6).The total number of J/ψ events collected with the BESIII detector was determined to be(10087±44)×10^(6),where the uncertainty is dominated by systematic effects,and the statistical uncertainty is negligible.

Finger pad friction and tactile perception of laser treated,stamped and cold rolled micro-structured stainless steel sheet surfaces

Tactile perception is a complex system,which depends on frictional interactions between skin and counter-body.The contact mechanics of tactile friction is governed by many factors such as the state and properties of skin and counter-body.In order to discover the connection between perception and tactile friction on textured stainless steel sheets,both perception experiments (subjective) and tactile friction measurements (objective) were performed in this research.The perception experiments were carried out by using a panel test method to identify the perceived roughness,perceived stickiness and comfort level from the participants.For the friction experiments,tactile friction was measured by a multi-axis force/torque transducer in vivo.The perceived stickiness was illustrated as an effective subjective stimulus,which has a negative correlation to the comfort perception.No significant evidence was revealed to the connection between the perceived roughness and comfort perception,and this relationship may be influenced by the participants' individual experience,gender and moisture level of skin.Furthermore,the kinetic tactile friction was concluded as an objective stimulus to the comfort perception with a negative correlation.

Plastic Effect on the Sliding Inception Bet ween a Cylinder and a Rigid Flat

The effec ts of mat erial plasticity and local slip on the sliding inception of asperity are studied in the present work.Firstly,a semi-analytical solution is derived under the full-stick condition to analyze the effect of material plasticity on sliding friction.Then,a friction model with contact stiffness criterion is proposed to study the cases from partial-slip condition to full-stick condition.Finite element simulations with the provided model are used to present the friction map.The friction coefficient of full-s tick interface converges at a st able value,approxima tely 0.3.Plasticity saturation appears as the normalized contact interference u*is larger than 3.A transition mechanism from slip-dominated to yield-dominated takes place in the sliding process.The simulation results are compared with the semi-analytical solution.

Search for the rare decay B^(0)→J/ψФ

A search for the rare decay B^(0)→J/ψФis performed using Pp collision data collected with the LHCb dete-ctor at centre-of-mass energies of 7,8 and 13 TeV,corresponding to an integrated luminosity of9 fb.No significant signal of the decay is observed and an upper limitof 1.1x 10^(-7)at 90%confidence level is set on the branching fraction.