[Clas_hadron] abstracts for DNP

[Volker Crede]

Dear Igor,

I agree with Mike. The "p pi eta" final state is extremely interesting but your talk is on single-eta production. I think that the mention of the "one-step excitation process" only causes confusion. You can just say: "... offers the feature of separating N* (I=1/2) resonance states from \Delta (I=3/2) states."

Cheers,

       Volker
 

On Jun 28, 2013, at 12:07 PM, Igor Senderovich wrote:

> Dear Viktor,
> 
> What I would call a two-step process is one in which the state de-excites via two emissions - say Delta excitation decaying with pion emission to an N* which then emits an eta. This illustrates a case when detection of an eta would not offer isospin filtering. I am just being careful to avoid such a counterexample to my statement.
> 
> All the best,
> -Igor
> 
> 
> ----- Original Message -----
> From: "Viktor Mokeev" <mokeev at jlab.org>
> To: "Igor Senderovich" <senderov at jlab.org>
> Cc: "clas hadron" <clas_hadron at jlab.org>
> Sent: Thursday, June 27, 2013 4:55:15 PM
> Subject: Re: [Clas_hadron] abstracts for DNP
> 
>  Dear Igor,
> 
> You abstracts look good.
> 
> Could you explain what you mean by one-step excitation processes?
> 
> Best Regards,
>                      Victor
> 
> ----- Original Message -----
> From: "Igor Senderovich" <senderov at jlab.org>
> To: "clas hadron" <clas_hadron at jlab.org>
> Sent: Thursday, June 27, 2013 11:30:15 AM
> Subject: [Clas_hadron] abstracts for DNP
> 
> Dear Colleagues,
> 
> I would like to submit the two abstracts that follow this e-mail for the meeting of the DNP and appreciate any feedback you can offer.
> Best regards,
> -Igor Senderovich
> 
> ----------
> For the mini-symposium (14e. Mini-Symposium on the Excited Nucleon State Spectrum and Structure):
> Title: Studies of $\eta$ photo-production in the baryon resonance excitation region with CLAS
> Abstract:
> Because the pseudoscalar $\eta$ meson has zero isospin, $\eta$ photo-production offers the feature of isolating N* (I=1/2) resonance states in one-step excitation processes. This ``isospin'' filter property can be very useful in helping disentangle the broad and overlapping excitations that make up the nucleon resonance spectrum. For that reason, a program of measurements on $\eta$ photo-production for the reaction $\gamma p \rightarrow \eta p$ has been conducted using the Hall B CEBAF Large Acceptance Spectrometer at Jefferson Lab. Results for the differential cross-section and for single- and double-polarization observables will be summarized. The general outlook for the ``complete experiment'' program for disentangling nucleon resonances decaying to the $p \eta$ channel will be discussed.
> 
> 
> A general DNP submission:
> Title: Double-polarization E and G observables in $\eta$ photo-production on the CLAS Frozen Spin Target
> Abstract:
> $\eta$ photo-production is an important tool in baryon spectroscopy, allowing isolation of N* (I=1/2) resonances in one-step excitation processes. Furthermore, it has long been recognized that due to significant overlapping of resonances in the baryon spectrum, differential cross-sections are not enough; measuring polarization observables is vital. Extensive data have been collected at Jefferson Lab in Hall B with circularly and linearly polarized tagged photon beams incident on longitudinally polarized protons provided by the Frozen Spin Target (FROST). The presentation will cover analysis and preliminary results of double-polarization observables E and G in $\eta$ photo-production - data entirely missing from the world database.
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