A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Astronomy and Astrophysics » Research
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

No WIMP Annihilation Observed In SMC



 
 
Thread Tools Display Modes
  #1  
Old March 5th 16, 10:33 AM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default No WIMP Annihilation Observed In SMC

http://arxiv.org/abs/1603.00965

Caputo et al

SMC is identified as a "natural" place to search for indirect WIMP DM
annihilation.

Six years of Fermi-LAT data used.

"no signal"

Agrees no signal and with stronger limits for LMC (and MWG center?)

RLO http://www3.amherst.edu/~rloldershaw
  #2  
Old March 8th 16, 09:15 AM posted to sci.astro.research
Craig Markwardt[_2_]
external usenet poster
 
Posts: 137
Default No WIMP Annihilation Observed In SMC

On Saturday, March 5, 2016 at 4:33:57 AM UTC-5, Robert L. Oldershaw wrote:
http://arxiv.org/abs/1603.00965

.....
Six years of Fermi-LAT data used.

"no signal"

Agrees no signal and with stronger limits for LMC (and MWG center?)


Thanks for quoting out of context. More context from the abstract
reveals, "we found that the SMC was well described by standard
astrophysical sources, and no signal from dark matter annihilation was
detected."

I.e. the Fermi analysis was not sensitive enough to detect to detect a
signal, which is different than claiming that Fermi detected a lack of
signal (which was not claimed).

And to be clear, there *IS* a claimed dark matter signal by Fermi from
the Milky Way galactic center.

CM
  #3  
Old March 9th 16, 09:17 AM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default No WIMP Annihilation Observed In SMC

On Tuesday, March 8, 2016 at 3:15:49 AM UTC-5, Craig Markwardt wrote:


And to be clear, there *IS* a claimed dark matter signal by Fermi from
the Milky Way galactic center.


Well, with all due respect, the FERMI group disagrees with you, if you
believe that the "claim" has any solid *empirical* basis. See for
example: http://arxiv.org/abs/1501.05464 .

Also did you see the thread I started entitled "WIMPs AWOL Again",
wherein I offered some additional evidence published in PRL. You might
be interested in the following important contribution of the authors
to this area of research: http://arxiv.org/abs/1506.05104 .

[Mod. note: reformatted, comment addressed to moderators removed --
please do not put comments addressed to moderators in your posts -- mjh]

RLO http://www3.amherst.edu/~rloldershaw
  #4  
Old March 11th 16, 09:10 AM posted to sci.astro.research
Craig Markwardt[_2_]
external usenet poster
 
Posts: 137
Default No WIMP Annihilation Observed In SMC

On Wednesday, March 9, 2016 at 3:17:32 AM UTC-5, Robert L. Oldershaw wrote:
On Tuesday, March 8, 2016 at 3:15:49 AM UTC-5, Craig Markwardt wrote:


And to be clear, there *IS* a claimed dark matter signal by Fermi from
the Milky Way galactic center.


Well, with all due respect, the FERMI group disagrees with you, ...


Fair enough. So you now understand the original paper's lack of
detection (i.e. an upper limit), is different than your claim of "no
signal?" The difference is in the statistics and in the expectations
of the relevant scientific models.

CM
  #5  
Old March 13th 16, 10:17 AM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default No WIMP Annihilation Observed In SMC

On Friday, March 11, 2016 at 3:11:18 AM UTC-5, Craig Markwardt wrote:


Fair enough. So you now understand the original paper's lack of
detection (i.e. an upper limit), is different than your claim of "no
signal?" The difference is in the statistics and in the expectations
of the relevant scientific models.


Well Craig, in scientific discussions would it not be rigorously
obvious that the curt phrase "no signal" comes with the inherent
implication that the any conclusion applies to this experiment, and at
this level of sensitivity?

It is extremely rare in science when some phenomena can be ruled out
absolutely and for all time. This is especially true when the result
is a NEGATIVE result.

Please correct me if I am wrong.

RLO ? http://www3.amherst.edu/~rloldershaw
  #6  
Old March 17th 16, 05:21 PM posted to sci.astro.research
Craig Markwardt[_2_]
external usenet poster
 
Posts: 137
Default No WIMP Annihilation Observed In SMC

On Sunday, March 13, 2016 at 5:17:49 AM UTC-4, Robert L. Oldershaw wrote:
On Friday, March 11, 2016 at 3:11:18 AM UTC-5, Craig Markwardt wrote:


Fair enough. So you now understand the original paper's lack of
detection (i.e. an upper limit), is different than your claim of "no
signal?" The difference is in the statistics and in the expectations
of the relevant scientific models.


Well Craig, in scientific discussions would it not be rigorously
obvious that the curt phrase "no signal" comes with the inherent
implication that the any conclusion applies to this experiment, and at
this level of sensitivity?


It's best not to assume the obvious in conversations with you. So if
you had read the paper, it should be obvious that the detection limit
established by the observations... wouldn't have been expected to
detect relevant dark matter signals. So why raise this paper as
interesting?

CM
  #7  
Old March 18th 16, 09:55 AM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default No WIMP Annihilation Observed In SMC

On Thursday, March 17, 2016 at 12:22:00 PM UTC-4, Craig Markwardt wrote:


It's best not to assume the obvious in conversations with you. So if
you had read the paper, it should be obvious that the detection limit
established by the observations... wouldn't have been expected to
detect relevant dark matter signals. So why raise this paper as
interesting?


I will let your false assumption that I had not read the paper pass,
and just point out that the authors of that paper unequivocally stated
that they thought it was important to look for a DM annihilation
signal from the SMC for good astrophysical reasons. They expected that
they might find one, but they did not.

Are you claiming that the authors, reviewers and the editor of the
journal that accepted it were all engaging in promoting unnecessary
and misleading research?

Please explain yourself.

RLO http://www3.amherst.edu/~rloldershaw
  #8  
Old March 30th 16, 08:22 AM posted to sci.astro.research
jacobnavia
external usenet poster
 
Posts: 105
Default No WIMP Annihilation Observed In SMC

Science magazine today:

http://science.sciencemag.org/conten.../1376.full.pdf

"It's crunch time", says Rocky Kolb, a theorist at the University of
Chicago (UC) in Illinois, comparing the WIMP quest to a football game.
"We're in the second half, maybe the fourth quarter. We haven't scored."
Elena Aprile, an experimentalist at Columbia University and leader of
the XENON team, says the new detector has a real shot at discovering
WIMPs: "They could be right around the corner." But, she adds, "We're
perhaps losing faith in the sense that we're not sure whether 1 ton or
even 10 tons will be enough to see anything."

Other dark matter researchers share her concerns. A few years ago, when
the biggest WIMP detector weighed a few kilograms, most thought that a
1-ton experiment would either find WIMPs or stick a dagger in the idea.
But generations of ever bigger detectors have come up empty, and
physicists are rethinking the argument for WIMPs and what it might take
to find them. They have bigger detectors in the works and are laying
plans for the ultimate WIMP detector. But even avid dark matter hunters
aren't sure that the giant detector is worth pursuing.

[snip]

..... physicists are anxious about its prospects. Their main concern is
that in 6 years of running, the LHC has found no evidence of
supersymmetry - the foundation of the WIMP model. It's not too late, as
until last year the LHC ran at only half energy. Still, "the 800-pound
gorilla in the room is the lack of any sign of supersymmetry coming from
the LHC," says Juan Collar, an experimentalist at UC.
To hedge their bets, dark matter researchers are working on even bigger
detectors. XENON1T is designed so that in 2 years it can be expanded to
create XENONnT, which would hold 7.5 metric tons of xenon. And
researchers with LUX are building a detector called LZ that should hold
10 metric tons of xenon and would come on line in 2019.
  #9  
Old March 30th 16, 10:29 PM posted to sci.astro.research
Jos Bergervoet
external usenet poster
 
Posts: 126
Default No WIMP Annihilation Observed In SMC

On 3/30/2016 9:22 AM, jacobnavia wrote:
...
.... physicists are anxious about its prospects. Their main concern is
that in 6 years of running, the LHC has found no evidence of
supersymmetry - the foundation of the WIMP model.


If dark matter is not super-symmetric particles, can it still
be one of the following, or are those also ruled out already?
1) Axions (say with 100ueV mass?)
2) Heavy Sterile neutrinos?
3) Primordial black holes?

--
Jos
  #10  
Old March 30th 16, 10:32 PM posted to sci.astro.research
Robert L. Oldershaw
external usenet poster
 
Posts: 617
Default No WIMP Annihilation Observed In SMC

On Wednesday, March 30, 2016 at 3:23:29 AM UTC-4, jacobnavia wrote:
Science magazine today:

http://science.sciencemag.org/conten.../1376.full.pdf

"It's crunch time", says Rocky Kolb, a theorist at the University of
Chicago (UC) in Illinois, comparing the WIMP quest to a football game.
"We're in the second half, maybe the fourth quarter. We haven't scored."
Elena Aprile, an experimentalist at Columbia University and leader of
the XENON team, says the new detector has a real shot at discovering
WIMPs: "They could be right around the corner." But, she adds, "We're
perhaps losing faith in the sense that we're not sure whether 1 ton or
even 10 tons will be enough to see anything."


Note that Dr. Aprile's real and clearly stated concern is whether the
detectors, existing and planned, "will be big enough".

There is a giant difference between losing confidence in the general
WIMP hypothesis, and losing confidence in our ability and/or
willingness to build something big/expensive enough to detect what
"must" exist.

Really, it is the same with the "sparticles" of SUSY, or WIMPs or
"strings". The proponents of these hypotheses firmly believe in their
existence and will assure us that they are to be found just over then
next energy/ detector size hill, or the next, or the next.

There is only one way the WIMP game can end, and that is if the dark
matter turns out to be something else entirely and the evidence is
undeniable.

If a genie offered me three wishes, I would say tell me what the dark
matter is and I'll forgo the other two wishes.

RLO ttp://www3.amherst.edu/~rloldershaw
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Fermi-LAT Collaboration Confirms Latest WIMP No-Show Robert L. Oldershaw Research 0 August 18th 11 08:44 AM
Annihilation of positron and eletron particles Skeu Astronomy Misc 32 May 17th 09 03:52 AM
Has Anybody Observed: Dennis Woos Amateur Astronomy 4 September 6th 07 05:16 AM
The Shuttle is a wimp diy-newby Space Shuttle 8 March 23rd 07 11:37 PM
I am a wimp Walt Amateur Astronomy 3 January 1st 07 05:03 PM


All times are GMT +1. The time now is 01:35 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.