[clas_members] Fwd: Daily Press posts article on Science paper

Volker Burkert burkert at jlab.org
Wed Oct 22 22:04:33 EDT 2014

CLAS Science in the News.

Thanks to all who built the CLAS and made it run at the highest 
luminosity of any large acceptance detector, thanks to the wide open 
trigger (electrons only), and thanks to all who where on shift (eg2) and 
took all the beautiful data in 2004, and thanks to the machine operators 
who managed to get beyond 5 GeV, and thanks to the diligent data miners, 
and thanks to DOE who funded all this..... we have some nice and 
unexpected results that made it in the newspaper tomorrow.

Sometimes the reward comes a decade later!
Keep it all up!


-------- Original Message --------
Subject: 	Daily Press posts article on Science paper
Date: 	Wed, 22 Oct 2014 16:28:13 -0400 (EDT)
From: 	Kandice Carter <kcarter at jlab.org>
To: 	Douglas Higinbotham <doug at jlab.org>, Larry Weinstein 
<weinstei at jlab.org>
CC: 	Bob McKeown <bmck at jlab.org>, Rolf Ent <ent at jlab.org>, Hugh 
Montgomery <mont at jlab.org>, Volker Burkert <burkert at jlab.org>, Cynthia 
Keppel <keppel at jlab.org>, Jim Raper <jraper at odu.edu>, John Warren 
<jwarren at jlab.org>, deborah magaldi <magaldi at jlab.org>


  Jeff Lab produces new data on nucleon pairings

By Tamara Dietrich 
<http://bio.tribune.com/tamaradietrich>tdietrich at dailypress.com

October 23, 2014

It's the mission of physicists to drill down and study the weirdness of 
the natural world, from the subatomic to the galactic.

Now data mining into experiments conducted at Jefferson Lab in Newport 
News has turned up new information about proton and neutron pairings in 
heavy nuclei, such as lead and iron, that will have other physicists 
tweaking their own research.

"We knew protons and neutrons paired up in heavier nuclei — we just 
didn't know how much," Doug Higinbotham, a staff scientist at Jefferson 
Lab, said Wednesday.

  * Topics <http://www.dailypress.com/topic>
  * Scientific Research
  * Physics
  * Old Dominion University

And since their understanding of such pairings was imperfect, he said, 
scientists who studied them had to work with imperfect formulations.

"Because calculations are so hard, people make simple approximations to 
calculate the system," said Lawrence Weinstein, a physics professor at 
Old Dominion University 
<http://www.dailypress.com/topic/education/colleges-universities/old-dominion-university-OREDU0000135.topic> in 
Norfolk. "This data is saying the approximation that was made has to be 
flipped. Previously we would say neutrons would have higher-than-average 
momentum. Now it's saying it's the other way around, because of the 

The two scientists describe those pairings as much like boys and girls 
on a dance floor, each moving at its own pace or momentum. But when 
protons and neutrons pair up in something called a short-range 
correlation, their momentum increases, generating greater speed.

They found this holds true even if there's a large number of protons and 
neutrons and if the number of protons and neutrons is very different 
from each other. Lead, for instance, has 1 1/2 neutrons for every 
proton, yet protons and neutrons still prefer to seek each other out, 
leaving far fewer proton/proton or neutron/neutron pairings.

"It's easier to figure out pairings if you just have six of one and six 
of the other," Weinstein said. "But once you start getting a lot — and 
lead is (a sum of) 208 protons and neutrons — the calculations just get 
too hard."

They say their findings alter some long-accepted theories about the 
nucleus, with implications for ultra-cold atomic gas systems and neutron 
stars — which are like a massive nucleus with 10 times more neutrons 
than protons.

"What it comes down to is, neutron stars are really cool," said 
Weinstein. "They're fascinating. And we want to understand how big they 
can be, how quickly they can cool down, how they form. And this 
measurement can affect our understanding of all of those."

Higinbotham and Weinstein, along with an international group of 
scientists, came up with their findings by analyzing data from an 
experiment conducted at the national lab in 2004. The two co-authored a 
paper on their work that just appeared in the online edition of the 
journal Science, and is expected to appear soon in the print version.

Jefferson Lab houses a large underground particle beam accelerator 
called the Continuous Electron Beam Accelerator Facility (CEBAF), which 
scientists from around the world use to try to unravel the mysteries of 
the building blocks of matter.

Since 2008, the facility has been undergoing a $338 million renovation 
to double CEBAF's energy capacity to 12 GeV, or 12 billion electron 
volts, to better understand the basic quark structure of subatomic 

/Dietrich can be reached by phone at 757-247-7892./

Copyright © 2014, Newport News, Va., Daily Press 

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