[b1_ana] Fwd: comments/questions to PR12-13-011

Mon Jun 10 15:18:00 EDT 2013

Also, for just the x-range we're looking over, we get:

------------------------------------------------------------------------------------------
For Miller, the integrated sums over particular ranges are:

Range                  & PDF Type        & Sum

0.15 < x < 0.5     & CTEQ5            & -0.00467
0.15 < x < 0.5     & MRST2001LO  & -0.00467
0.15 < x < 0.5     & MSTW2008LO & -0.00467

------------------------------------------------------------------------------------------
For Misak, the integrated sums over particular ranges are:

Range                & PDF Type        & Sum with vn & Sum with lc

0.245 < x < 0.5 & CTEQ5            & -0.000191 & -0.000141
0.245 < x < 0.5 & MRST2001LO  & -0.000152    & -0.000112
0.245 < x < 0.5 & MSTW2008LO & -0.000184    & -0.000136

------------------------------------------------------------------------------------------
For Kumano, the integrated sums over particular ranges are:

Range                  & PDF Type        & Sum Without Sea & Sum With Sea

0.15 < x < 0.5     & CTEQ5            & -0.000700             & -0.00053
0.15 < x < 0.5     & MRST2001LO  & -0.000553             & -0.00030
0.15 < x < 0.5     & MSTW2008LO & -0.000718             & -0.00053

Take care,
Ellie

On Mon 10 Jun 2013 03:09:34 PM EDT, Elena Long wrote:
>
> test of Close-Kumano sum rule - it is very hard to do such test with
> limited coverage in x, may be some
> estimates of contribution measured/extrapolated can be done for
> specific models. For the models mentioned
> on page 17 - can one get some idea what would be the contribution in
> measured range?
>
> RESPONSE : Yes, this in an excellent suggestion. G. Miller and M.
> Sargian have provided us their curves. We need to integrate to see the
> contributions for x<0.15 and x>0.5. (Ellie, I think you have these
> now. Can you look into this?)
>
> ------------------------------
>
> Ellie:
> The calculations below show the integral over certain x ranges for
> three different types of PDFs used in the calculation of b1. They were
> calculated using step sizes of x=0.001 with INT(b1,x) =
> SUM(b1(x)*stepsize) where b1(x) is a calculate value of b1 at a
> particular x value.
>
> ------------------------------------------------------------------------------------------
> For Miller, the integrated sums over particular ranges are:
>
> Range & PDF Type & Sum
>
> 0.0001 < x < 0.998 & CTEQ5 & -0.00931
> 0.0001 < x < 0.998 & MRST2001LO & -0.00931
> 0.0001 < x < 0.998 & MSTW2008LO & -0.00931
>
> 0.0001 < x < 0.15 & CTEQ5 & +0.00200
> 0.0001 < x < 0.15 & MRST2001LO & +0.00200
> 0.0001 < x < 0.15 & MSTW2008LO & +0.00200
>
> 0.0001 < x < 0.5 & CTEQ5 & -0.00267
> 0.0001 < x < 0.5 & MRST2001LO & -0.00267
> 0.0001 < x < 0.5 & MSTW2008LO & -0.00267
>
> 0.5 < x < 0.998 & CTEQ5 & -0.00664
> 0.5 < x < 0.998 & MRST2001LO & -0.00664
> 0.5 < x < 0.998 & MSTW2008LO & -0.00664
>
> ------------------------------------------------------------------------------------------
> For Misak, the integrated sums over particular ranges are:
>
> Range & PDF Type & Sum with vn
> & Sum with lc
>
> 0 < x < 0.245 & N/A & Model does not apply
>
> 0.245 < x < 0.998 & CTEQ5 & -0.000181 & -0.000135
> 0.245 < x < 0.998 & MRST2001LO & -0.000146 & -0.000109
> 0.245 < x < 0.998 & MSTW2008LO & -0.000172 & -0.000129
>
> 0.245 < x < 0.5 & CTEQ5 & -0.000191 &
> -0.000141
> 0.245 < x < 0.5 & MRST2001LO & -0.000152 & -0.000112
> 0.245 < x < 0.5 & MSTW2008LO & -0.000184 & -0.000136
>
> 0.5 < x < 0.998 & CTEQ5 & +0.000010 &
> +0.000006
> 0.5 < x < 0.998 & MRST2001LO & +0.000006 & +0.000003
> 0.5 < x < 0.998 & MSTW2008LO & +0.000012 & +0.000007
>
> ------------------------------------------------------------------------------------------
> For Kumano, the integrated sums over particular ranges are:
>
> Range & PDF Type & Sum Without Sea&
> Sum With Sea
>
> 0.0001 < x < 0.998 & CTEQ5 & +0.00183 &
> +0.00820
> 0.0001 < x < 0.998 & MRST2001LO & +0.000604 & +0.0104
> 0.0001 < x < 0.998 & MSTW2008LO & +0.000266 & +0.00767
>
> 0.0001 < x < 0.15 & CTEQ5 & +0.00296 &
> +0.00901
> 0.0001 < x < 0.15 & MRST2001LO & +0.00147 & +0.0109
> 0.0001 < x < 0.15 & MSTW2008LO & +0.00143 & +0.00849
>
> 0.0001 < x < 0.5 & CTEQ5 & +0.00226 &
> +0.00848
> 0.0001 < x < 0.5 & MRST2001LO & +0.000917 & +0.0106
> 0.0001 < x < 0.5 & MSTW2008LO & +0.000712 & +0.00796
>
> 0.5 < x < 0.998 & CTEQ5 & -0.00043
> & -0.00028
> 0.5 < x < 0.998 & MRST2001LO & -0.000313 & -0.0002
> 0.5 < x < 0.998 & MSTW2008LO & -0.000446 & -0.00029
>
>
>
> Take care,
> Ellie
>
> Elena Long, Ph.D.
> Post Doctoral Research Associate
> University of New Hampshire
> elena.long at unh.edu
> ellie at jlab.org
> http://nuclear.unh.edu/~elong
> (603) 862-1962
> On 06/09/2013 11:07 PM, Karl Slifer wrote:
>>
>>
>> Hi all,
>>
>> Below please find a draft response to the readers. I'd appreciate
>> any/all feedback.
>>
>> Thanks to Oscar and Dustin for sending comments already. I hope I
>> have incorporated them satisfactorily, but let me know if not.
>>
>> Dustin : any ETA for the updates to the technote? Ideally we can send
>> them this short email and then provide your note for the full details.
>> Most important would be to clarify the overall drift numbers, as I
>> had the same confusion that Ellie raised.
>>
>> I'll have time to work on this tomorrow morning and early afternoon,
>> but have to leave for DC mid afternoon. I'd love to get a response
>> to Ewa before then if possible.
>>
>> thanks much,
>>
>> -Karl
>>
>>
>> -----------------------------
>>
>> The measurement is very sensitive to the systematic effects and good
>> control of them is the
>> key point. Therefor I would like to know if there are any estimates
>> of expected size of effects from:
>>
>> RESPONSE: We agree with the TAC assessment that systematic errors
>> from drifts must be mitigated, but
>> that they are manageable with a combination of
>> hardware upgrades and a dedicated collaboration
>> effort. We note that the recent g2p experiment
>> involved a similar situation where a significant
>> commitment was made to install and run this
>> polarized target, but separate groups were tasked
>> with substantial tasks of beamline, DAQ and
>> detector upgrades. We are grateful to the TAC for
>> pointing out several effects which were not
>> explicitly discussed in our submitted proposal. We
>> have written a short note discussing each of
>> these and conclude that the overall systematic
>> uncertainty is still of the same order as
>> estimated in the proposal.
>>
>> 1. beam - one aspect is the stability in terms of position and divergency
>> this can change acceptance and produce false asymmetries
>>
>> RESPONSE: (The TAC report pointed out that the false asymmetries from
>> beam position drifts are easily
>> removed by "regression". Can someone fill in the
>> details? I assume that this just means
>> that the parity feedback on position is very
>> good, but we need some numbers/examples to
>> back this up. This is dealt with in section
>> 1.1.4 of the note, but there are few details.)
>>
>> 2 beam polarization - how the unpolarized beam will be obtained what
>> kind of effects are
>> expected from beam polarization (ie. to which level exact
>> averaging of opposite beam polarity
>> is needed and how the phase space of the beam is polarization
>> dependent)
>>
>> RESPONSE: JLab E06-010 (Transversity) spin-averaged a highly
>> polarized (~80%) beam in order to
>> obtain an "unpolarized" beam. The parity
>> feedback allowed for knowledge of the residual
>> beam polarization at the 2.2*10^{-5} level,
>> according to the lumi monitors. Please see attached
>> plot, which shows the beam asymmetry from that
>> experiment.
>>
>>
>> 3. temperature effects on the efficiency (and stability of the
>> detectors allignment) - proposed scheme
>> of polarization reversals will give data with target
>> polarization during the day and unpolarized
>> at night or vice versa. This can introduce false asymmetry
>> related to any kind of temperature
>> dependence in efficiency or allignment. Was it estimated ? Are
>> there any studies of this kind of effects
>> in previous experiments?
>>
>> RESPONSE: (This could be addressed by the transversity slides, but
>> I'm not sure if the pion yield plot
>> addresses this. The main sensitivity to
>> temperature will be the BCMs and Dave has plans
>> to isolate them, but I don't have any details of
>> that yet.)
>>
>>
>>
>> 4. for the drift of efficiency and its time dependence (page 25)
>> linear evolution in time is assumed.
>> for which effects it is justified? It is clear that for example
>> changes in packing factor of dilution factor
>> can have "step like" characteristics. Are there any ideas to
>> what level such effects can be controlled
>> during the run?
>>
>> RESPONSE : (Linear and sinusoidal drifts are the only type that I've
>> seen. Higher orders could theoretically
>> be present, but if they were I suppose they
>> would become an issue for all experiments, not just ours.)
>> "Step-like" changes in the packing factor or
>> dilution factor have only been observed once in 700 hours
>> of running the polarized target. It was
>> immediately obvious from the change in polarization. If it
>> occurs during this experiment, it would impact
>> only a single pol/unpol cycle, which is either a 12 hour or
>> 24 hour portion of data. This data would need
>> to be either discarded or handled with care.
>>
>>
>> In the proposal "consistency checks on measured cross section for
>> each run" is mentioned.
>> What precisely is meant? At what level it can be done for the
>> proposed measurement? Please give
>> more detail, especially on the precision of such test.
>>
>> RESPONSE : Typically we can monitor the unpolarized yields to the
>> better than 1% level. Luminosity monitors
>> installed around the beamline can be monitored
>> to the ?? level (J.P.?)
>>
>>
>> The other test mentioned in the proposal, where I would like to have
>> some more comments on is "the
>> measurements of dilution and packing factor - with carbon target "-
>> what exactly is planed and which
>> precision can be obtained? is it included in the beam time estimate?
>>
>> RESPONSE: The polarized target material is deuterated ammonia (ND_3).
>> We determine the dilution factor by the ratio of
>> simulated radiated rates on D to total
>> rates. The pf is calculated by interpolating the
>> ND3 measured rates between simulated
>> rates for different packing factors, with the
>> simulation calibrated by the measured rates
>> on a carbon target of known thickness. The
>> systematic uncertainty of this process
>> is at the 4% level. It is important to note that
>> the dilution factor is a scale factor so the
>> uncertainty is an overall scale factor. We have
>> 6 hours assigned to this task in our overhead table 4.
>> This is a relatively short time since all that is
>> needed is to measure the unpolarized cross section
>> from a carbon disk, and the rate is usually quite
>> high.
>>
>>
>> It would be interesting to see comparison of expected statistical
>> errors in each bin with expected false
>> asymmetries from time variation of beam and efficiency/acceptance.
>>
>> RESPONSE: We now have plots graphically showing the full systematic
>> uncertainty, both from the normalization
>> dependent factors and the possible drifts. The
>> plots are shown in the technote.
>>
>>
>> What are the arguments for proposed binning in x?
>> the last bean is clear, as much data in this configuration as
>> possible, but splitting of SHMS data taking
>> in 3 intervals is not discussed from the optimalization point of
>> view, it would be good to have it in the
>> presentation.
>>
>> RESPONSE : (Hmm. Not sure how to answer this. Simple answer is that
>> the points represent the largest
>> spread in x that allows a reasonable overlap
>> with HERMES in a reasonable amount of beam-time.
>> Ellie has optimized to avoid large systematics
>> from F1, and suppression of rates. )
>>
>>
>>
>> In general, also the authors call the measurement "ratio method" it
>> is the cross section difference method
>> as the two data sets are taken at different time. Advantage of "ratio
>> method" can be fully used when two
>> target cels are exposed at the same time and next order is reversed.
>> Such configuration allows several
>> additional cross checks, but requires two cell target.
>>
>> RESPONSE : We have examined a two cell configuration, and while it is
>> attractive for the reason you point
>> out, it was not clear at the time of the
>> proposal submission that it significantly reduced the
>> overall systematic uncertainty. We will
>> continue to examine this option and are open to using
>> it if we are convinced the systematic
>> improvement is significant.
>>
>>
>> test of Close-Kumano sum rule - it is very hard to do such test with
>> limited coverage in x, may be some
>> estimates of contribution measured/extrapolated can be done for
>> specific models. For the models mentioned
>> on page 17 - can one get some idea what would be the contribution in
>> measured range?
>>
>> RESPONSE : Yes, this in an excellent suggestion. G. Miller and M.
>> Sargian have provided us their curves.
>> We need to integrate to see the
>> contributions for x<0.15 and x>0.5. (Ellie, I think you have these
>> now. Can you look into this?)
>>
>>
>>
>>
>> _______________________________________________
>> b1_ana mailing list
>> b1_ana at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/b1_ana
>
>
>
>
> _______________________________________________
> b1_ana mailing list
> b1_ana at jlab.org
> https://mailman.jlab.org/mailman/listinfo/b1_ana
> -- 
> Elena Long, Ph.D.
> Post Doctoral Research Associate
> University of New Hampshire
> elena.long at unh.edu
> ellie at jlab.org
> http://nuclear.unh.edu/~elong
> (603) 862-1962