Recent heavy-flavour results from ATLAS

Using template ﬁt to estimate signal and background. Background : pion or kaon decays in ﬂight, muons produced from the decays of particles produced in hadronic showers, and mis-associations of ID and MS tracks. Similar trends show in non-prompt 𝐽/𝜓 muclear modification factor. Using template ﬁt to estimate signal and background. Background : pion decays in ﬂight, kaon decays in ﬂight, muons produced by secondary interactions of prompt particles, and misassociations. 𝑅 𝐴𝐴 shows a centrality-dependent suppression that is 𝑝 𝑇 -independent within uncertainties.


Motivations
The ATLAS detector  Υ candidates ATLAS-CONF-2015-050 The corrected Υ yields are extracted from binned least square fits performed on .
G -single Gaussian function CB -Crystal Ball function erf -error function E -exponential function P -2nd order polynomial function -fraction of the Gaussian function in the signal SQM Jing Chen (USTC) 7 Heavy flavor muon candidates Using template fit to estimate signal and background.
Two-particle h-correlation functions in 8.16 TeV p+Pb collisions ATLAS-CONF-2017-006 Background: pion or kaon decays in flight, muons produced from the decays of particles produced in hadronic showers, and mis-associations of ID and MS tracks. Nuclear modification factor -prompt / The prompt / modification factor no obvious or * dependence. • Anisotropies are measured using the two-particle correlation method • v 2 at the two collision energies are quite similar and the difference between them is covered by the systematic uncertainties.
• The muon-v 2 values are largest at 4 GeV and decrease with increasing Azimuthal Anisotropy ATLAS-CONF-2017-006 • The v 2 for charged particles increases with ℎ at low ℎ and eventually saturates for ℎ >150. However even at the lowest measured multiplicity, a large v 2 is observed. • The v 2 for the muons, over this range the measurements are consistent with no ℎ dependence.
• Here a significant dependence of v 2 on Δ is observed. On the other hand the template v 2 vary by less than 10% over the whole Δ range. (A strong bias in the v 2 values from dijets, which are accounted for and removed in the template fits.)
(2S) to / double ratio ATLAS-CONF-2016-109 • The suppression of prompt (2S) relative to / indicate the more tightly bound quarkonium system, the / , survives the temperature of the hot dense medium with a higher probability than the more loosely bound quarkonium, the (2S). • Non-prompt mesons(originate from b-quarks) were essentially always formed outside the medium. The unity double ratio was expected.
Nuclear modification factor -HF muon HF v 2 decreases with , but is still significant at 10 GeV.
At fixed , the v 2 values show a systematic variation with centrality that is characteristic of elliptic flow measurements.

Summary Quarkonia
• Measured in p+Pb and Pb+Pb systems.
• The Pb+Pb results in high range show strong suppression with increasing centrality.
• Proton-lead interactions show little modification of the ground charmonium state. • Upsilons have been studied in p+Pb and found to show only a modest suppression. • New quarkonia results based on p+Pb at 5TeV and pp at 5TeV will come soon.

Heavy flavor muons
• Measured in Pb+Pb and p+Pb collisions.
• Fourier coefficients associated with the azimuthal modulation ( 2) has been measured. • of / production is found to depend strongly on . No significant rapidity dependence is observed.
• In pp and pPb collisions, this trend consistent with each other.
• measured in Pb+Pb collisions as a function of does not depend on the collision centrality class. The measured non-prompt / and 2S cross sections show good agreement with FONLL predictions.
The measured prompt / and 2S cross sections show good agreement with NRQCD predictions.
2 to J/ double ratio ATLAS-CONF-2015-023 The prompt 2 to J/ double ratio show no obvious rapidity dependence, but a decreasing trend as the event activity increases.