STAR HardProbes PWG

[Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>]

Hello HP-pwg and Lijuan,

After discussing at last hp-pwg meeting and collecting inputs,

it is now clear that BHT1 with the following threshold is not useful for 
any jet and hf measurements.
> > > > > BHT1-VPD100: the threshold is 11

Only required and useful triggers are the followings.
> > > > > For Run23, we have the following:
> > > > > BHT2-VPD100: the threshold is 18
> > > > > BHT3: the threshold is 25

If you have any further comments and feedback, you are welcome.

Thank you
Nihar


On 2023-06-22 10:08, Nihar Sahoo via Star-triggerboard-l wrote:
> Hello Rongrong,
>
> Thank you for this information and elaboration.
>
> Then I think for HT1 we may set the threshold 15 (~3.5 GeV) instead of
> 11 for any jet related analysis and pre-scale cab be set <20. For any
> future jet physics analysis if someone comes with new
> idea/measurement.
>
> And for other HT threshold, we can keep as it is. What do you think?
>
> > > > > For Run23, we have the following:
> > > > > BHT2-VPD100: the threshold is 18
> > > > > BHT3: the threshold is 25
>
> We may discuss in details this at today's hp-pwg meeting.
>
> Best
> Nihar
>
>
> On 2023-06-21 22:31, Ma, Rongrong wrote:
> > Hello Again
> >
> > Jamie just mentioned that the 20 B MB events should correspond to
> > about 3 nb^-1. This corresponds to what a HT trigger with pre-scale of
> > about 13 can sample.
> >
> > Best
> > Rongrong
> >
> > > On Jun 21, 2023, at 12:41 PM, Ma, Rongrong via Star-hp-l 
> > > <star-hp-l AT lists.bnl.gov> wrote:
> > >
> > > Hello Nihar, Lijuan
> > >
> > > For the Upsilon paper we just published, a threshold of 18 (HT2) was 
> > > used. We also published Jpsi cross section in 500 GeV pp collisions 
> > > using HT2, which covers Jpsi down to 4 GeV/c. The MB sample (20 B) we 
> > > aim to record should be sufficient for covering low-pT Jpsi, and 
> > > Upsilon even though Upsilon can already be measured down to 0 pT with 
> > > HT2 trigger.
> > >
> > > Furthermore, the 20 B MB events roughly correspond to 2 nb^-1 of 
> > > luminosity. So any HT trigger with a pre-scale larger than 20 will 
> > > not be very useful, which I think is the case for our current HT1 
> > > (threshold = 11). So I think it only makes sense to raise the 
> > > threshold to 15 if there is physics program requiring it, such that 
> > > the pre-scale can be smaller than 20. Otherwise, we should probably 
> > > drop the HT1 trigger.
> > >
> > > For the question of whether we can use threshold 15 for Upsilon, the 
> > > answer is yes, However, the issue is that we will not be able to 
> > > sample the full luminosity with this threshold, which effectively 
> > > reduces the statistics. So I do not see a strong motivation there.
> > >
> > > Best
> > > Rongrong
> > >
> > > > On Jun 21, 2023, at 10:57 AM, Nihar Sahoo via Star-hp-l 
> > > > <star-hp-l AT lists.bnl.gov> wrote:
> > > >
> > > > Dear Lijuan,
> > > >
> > > > sorry, I could not join yesterday trigger board meeting.
> > > >
> > > > As per BUR 23+25, we have mainly Jet substructure, gamma+jet, J/psi 
> > > > and Upsilon physics program in Au+Au.
> > > >
> > > > 1) For Jet substructure measurement, HT1 and HT2 with 11 (~2.6 GeV) 
> > > > and 18 (~4.2 GeV), respectively, would be OK.
> > > > 2) For gamma+jet: BHT3(+L2gamma) 25 (~5.9 GeV); I think this is same 
> > > > with previous runs; so it is OK.
> > > > 3) J/psi: probably Lower HT1 threshold 11 (~2.6 GeV)
> > > > 4)Upsilon: both HT1,2 with threshold 11 and 18 would be Ok.
> > > > But need to confirm from PAs (Others can comment) if it is Ok to use 
> > > > HT2 as 15 (~3.5) for Upsilon analysis or not.
> > > >
> > > > Thank you
> > > > Nihar
> > > >
> > > >
> > > > > For Run23, we have the following:
> > > > > BHT1-VPD100: the threshold is 11
> > > > > BHT2-VPD100: the threshold is 18
> > > > > BHT3: the threshold is 25
> > > >
> > > > On 2023-06-21 18:54, ruanlj via Star-triggerboard-l wrote:
> > > > > Hi All,
> > > > > After yesterday's trigger board meeting, I went to check the BHT
> > > > > thresholds for Run 16.
> > > > > As mentioned by Rongrong, there was no BHT2 trigger for hard probes 
> > > > > physics.
> > > > > There were two triggers:
> > > > > BHT1-VPD10: the threshold was set to 16 and later was changed to 15
> > > > > BHT3: the threshold was 25
> > > > > For Run23, we have the following:
> > > > > BHT1-VPD100: the threshold is 11
> > > > > BHT2-VPD100: the threshold is 18
> > > > > BHT3: the threshold is 25
> > > > > My question to hard probes pwg/experts: is the current threshold
> > > > > setting for BHT triggers good for your physics program?
> > > > > Lijuan
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