[Tensor] [EXTERNAL] Re: Tensor Experiments Meeting today at 4pm (ET)

Wed May 24 15:55:27 EDT 2023

Hi b1 fans,

At the tensor meting yesterday I shared a plot of the Q^2 dependence of the leading and higher-twist model tensor structure functions b_{1,2,3,4} from table 1 of Cosyn et al., to explore connections of the HT pieces with their expected contributions to A_zz

https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1103_PhysRevD.95.074036&d=DwIFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=mbL-4Mr65FbyCWqCw73luw&m=y_1ApcqaM_Y3P5hLcSHErFYFv1KCPtzEZYGpHWTSEj1oBzLIkQHKrJ6btmQvPZug&s=AuBu9vqOZ4sX9SlvwU_bXvmohn0yviKDC7qSA5TEsjk&e= 

Wim clarified that the Q^2 dependence of the model tensor SFs is not directly related to their effective contributions to the tensor amplitudes, because there are kinematical factors associated with the SFs, per eq. (32) of the reference.

The model SFs calculated at the HERMES kinematics show a significant Q^2 dependence, including zero crossings except for b_3 always < 0, in the range of interest, see top panel of attached file.

It's not clear if this Q^2 dependence may be an artifact of the Q^2 - x_Bjorken correlation of the measured data so I plotted the values of Q^2 vs x for the HERMES data and for the Hall C measurement.

As the bottom panel of the attachment shows, both the HERMES data and the Hall C measurement have a strong correlation between the two kinematical variables. Moreover, it's seen that at fixed x_B, the Q^2 of the Hall C data is about 1/2 that of the HERMES kinematics. These features were already seen in figs. [3] (HERMES kinematics) and [8], top panel (Hall C) of our proposal.

https://userweb.jlab.org/~slifer/b1/tensor_b1_2013_submitted.pdf

However, at the time, no information regarding the size of HT contributions to A_zz or its Q^2 dependence was available, except theory estimates that HT effects might be of the order of a few percent of leading twist.

Since the reference's model SFs, especially b_4 but also b_3,  are seen to change rapidly with Q^2, it seems that to make meaningful comparisons and estimates of expected relative leading and HT contributions to A_zz, having values of the model SF's vs Q^2 at fixed x would be very useful, probably better than having values just at the centroids of the experimental data's kinematics which, as figs. [3] and [8] of our proposal show, cover substantial areas of Q^2 - x space. Having such information would definitely be of aid in deciding about the choice of angle between the target field and the beam.

Cheers,

Oscar

________________________________________
From: Tensor <tensor-bounces at jlab.org> on behalf of Karl Slifer via Tensor <tensor at jlab.org>
Sent: Tuesday, May 23, 2023 9:23 AM
To: tensor at jlab.org; Fernando, M. A. Ishara Priyasad (cee9hc)
Subject: [Tensor] [EXTERNAL] Tensor Experiments Meeting today at 4pm (ET)

Reminder of Tensor experiments meeting Tuesday at 4pm (ET)

https://urldefense.proofpoint.com/v2/url?u=https-3A__unh.zoom.us_j_97641757857&d=DwIFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=mbL-4Mr65FbyCWqCw73luw&m=y_1ApcqaM_Y3P5hLcSHErFYFv1KCPtzEZYGpHWTSEj1oBzLIkQHKrJ6btmQvPZug&s=6Qvt5HV2PsS-WkCEaxl_1ZO0-zwn6le0FYsISjk9ZHw&e= <https://urldefense.proofpoint.com/v2/url?u=https-3A__nam12.safelinks.protection.outlook.com_-3Furl-3Dhttps-253A-252F-252Furldefense.proofpoint.com-252Fv2-252Furl-253Fu-253Dhttps-2D3A-5F-5Funh.zoom.us-5Fj-5F97641757857-2526d-253DDwMFAg-2526c-253DCJqEzB1piLOyyvZjb8YUQw-2526r-253DmbL-2D4Mr65FbyCWqCw73luw-2526m-253DmO2KcBS32FUa51mzNtpWHFfa-5FLSkM77Nqd2sdCU1GFPOlXTYORNdKqVag5pZdUE3-2526s-253DOWJFhL6DTu5zeeemfdmzsRmY-5FB6ywmFmGP5RDKuLSek-2526e-253D-26data-3D05-257C01-257Ckarl.slifer-2540unh.edu-257Cd2128e807f2d43b5f0ac08db27091521-257Cd6241893512d46dc8d2bbe47e25f5666-257C0-257C0-257C638146692213753801-257CUnknown-257CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0-253D-257C3000-257C-257C-257C-26sdata-3D8tFreWg7qrB7Vl5zpyLqCG6ydMjy4FivNRPp9Y0tWns-253D-26reserved-3D0&d=DwMFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=mbL-4Mr65FbyCWqCw73luw&m=u1Fzm3KVZCl-5pm_pTmS7yeIk0A27_vZYa0_xrgerzUrhEapfc_UTm6_I7NYpKUe&s=L-j5WmVQ5dhIUILvW9h_jH0oZbQ9ekdY4S1_ydVBVVc&e=>

Please send me any other items to add to the agenda

Agenda

  1.  Review of Jeopardy Docs
  2.  Transverse running update: KS
  3.  Higher Twist contamination : Wim C
  4.  AOB

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