Any links on this argument? If we do assume that dark matter is made of WIMPs and that they *were* approximately in thermal equilibrium not long after the Big Bang, does the argument imply an upper limit on the collider energy needed to observe them, because WIMPs at higher energies than this limit would be inconsistent with cosmological observations about dark matter?
On Thu, Aug 10, 2023 at 7:58 AM smitra <smi...@zonnet.nl> wrote: > A more model independent argument (which does have loopholes) goes as > follows. The weaker WIMPS interact with themselves and with baryons, the > sooner after the Big Bang they decouple, leading to a higher present-day > abundance. Then with the present-day abundance fixed, this implies > limits on the parameters describing WIMPS. And it becomes more and more > difficult to accommodate for WIMS with smaller and smaller small > cross-sections. But dark matter that has extremely weak interactions and > self-interactions would never have been in thermal equilibrium, which is > a possible loophole out of this no-go argument. > > Saibal > > On 10-08-2023 01:42, Jesse Mazer wrote: > > Does the idea that colliders should have already found WIMPs depend on > > the "naturalness" idea at > > https://en.wikipedia.org/wiki/Naturalness_(physics) which requires > > supersymmetric particles at those energies in order to solve the > > "hierarchy problem", or are there independent reasons to think that if > > WIMPs existed they should already have been found? I've read that > > those who endorse the string theory "landscape" idea see anthropic > > fine-tuning as an alternative to naturalness and thus didn't predict > > that supersymmetric particles would likely be found at LHC energies, > > for example Leonard Susskind's 2004 paper at > > https://arxiv.org/abs/hep-ph/0406197v1 said the following on pages > > 1-2: > > > > 'If the Landscape and the Discretuum are real, the idea of naturalness > > must be replaced with something more appropriate. I will adopt the > > following tentative replacement: First eliminate all vacua which do > > not allow intelligent life to evolve. Here we need to make some > > guesses. I’ll guess that life cannot exist in the cores of stars, > > cold interstellar dust clouds or on planets rich in silicon but poor > > in carbon. I’ll also guess that black holes, red giants and pulsars > > are not intelligent. > > > > 'Next scan the remaining fraction of vacua for various properties. If > > the property in question is common among these “anthropically > > acceptable” vacua then the property is natural. By common I mean > > that some non-negligible fraction of the vacua have the required > > property. If however, the property is very rare, even among this > > restricted class, then it should be deemed unnatural. Of course there > > is no guarantee that we are not exceptional, even among the small > > fraction of anthropically acceptable environments. It is in the nature > > of statistical arguments that rare exceptions can and do occur. > > > > Michael Douglas has advocated essentially the same definition although > > he prefers to avoid the use of the word anthropic wherever possible, > > and substitute “phenomenologically acceptable”. We have both > > attempted to address the following question: Are the vacua with > > anthropically small enough cosmological constants and Higgs masses, > > numerically dominated by low energy supersymmetry or by supersymmetry > > breaking at very high energy scales [8][7]? In other words is low > > energy supersymmetry breaking natural? My conclusion–I won’t > > attempt to speak for Douglas–is that the most numerous “acceptable > > vacua” do not have low energy supersymmetry. Phenomenological > > supersymmetry appears to be unnatural.' > > > > On Sat, Aug 5, 2023 at 5:26 PM Lawrence Crowell > > <goldenfieldquaterni...@gmail.com> wrote: > > > >> One weakness with this idea is it depends upon WIMP theory. This is > >> where the DM particles are weak interacting and Majorana. They are > >> their own anti-particle as a result annihilate themselves. The > >> problem is that detectors means to find WIMPS have come up with > >> nothing. DM appears to exist, but it may not be a weakly interacting > >> particle or WIMP. > >> > >> LC > >> > >> On Sunday, July 16, 2023 at 6:58:19 AM UTC-5 John Clark wrote: > >> > >>> As early as 2012 scientists predicted that the Hubble telescope > >>> would see something they called a "Dark Star". > >>> > >>> Observing supermassive dark stars with James Webb Space Telescope > >>> [1] > >>> > >>> They theorized in the early universe Dark Matter, whatever it is, > >>> must've been much more densely concentrated than it is today, and > >>> if Dark Matter particles are their own antiparticles as many think > >>> then their annihilation could provide a heat source, they could > >>> keeping star in thermal and hydrodynamic equilibrium and prevent > >>> it from collapsing. They hypothesized something they called a > >>> "Dark Star '', it would be a star with a million times the mass of > >>> the sun and would be composed almost entirely of hydrogen and > >>> helium but with 0.1% Dark Matter. A Dark Star would not be dark > >>> but would be 10 billion times as bright as the sun and be powered > >>> by dark matter not nuclear fusion. > >>> > >>> Astronomers were puzzled by pictures taken with the James Webb > >>> telescope that they interpreted to be bright galaxies just 320 > >>> million years after the Big Bang that were much brighter than most > >>> expected them to be that early in the universe, a recent paper by > >>> the same people that theorized existence of Dark Stars claim they > >>> could solve this puzzle. They claim 3 of the most distant objects > >>> that the Webb telescope has seen are point sources, as you'd > >>> expect from a Dark Star, and their spectrum is consistent with > >>> what they predicted a Dark Star should look like. With a longer > >>> exposure and a more detailed spectrum, Webb should be able to tell > >>> for sure if it's a single Dark Star or an early galaxy made up of > >>> tens of millions of population 3 stars. > >>> > >>> Supermassive Dark Star candidates seen by JWST [2] > >>> > >>> John K Clark See what's on my new list at Extropolis [3] > >>> > >>> 3vy > >> > >> -- > >> You received this message because you are subscribed to the Google > >> Groups "Everything List" group. > >> To unsubscribe from this group and stop receiving emails from it, > >> send an email to everything-list+unsubscr...@googlegroups.com. > >> To view this discussion on the web visit > >> > > > https://groups.google.com/d/msgid/everything-list/e8e41a06-7e91-4ac2-a636-b7481ffd1398n%40googlegroups.com > >> [4]. > > > > -- > > You received this message because you are subscribed to the Google > > Groups "Everything List" group. > > To unsubscribe from this group and stop receiving emails from it, send > > an email to everything-list+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > > > https://groups.google.com/d/msgid/everything-list/CAPCWU3LvD%3DBUJH8hNeWGbM6p%2BSfriLZr3JP82PiUbGKaxqUg%2BA%40mail.gmail.com > > [5]. > > > > > > Links: > > ------ > > [1] > > https://academic.oup.com/mnras/article/422/3/2164/1043351?login=false > > [2] https://www.pnas.org/doi/10.1073/pnas.2305762120 > > [3] https://groups.google.com/g/extropolis > > [4] > > > https://groups.google.com/d/msgid/everything-list/e8e41a06-7e91-4ac2-a636-b7481ffd1398n%40googlegroups.com?utm_medium=email&utm_source=footer > > [5] > > > https://groups.google.com/d/msgid/everything-list/CAPCWU3LvD%3DBUJH8hNeWGbM6p%2BSfriLZr3JP82PiUbGKaxqUg%2BA%40mail.gmail.com?utm_medium=email&utm_source=footer > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to everything-list+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/everything-list/e5e58252046554ec5b898c274b90ba76%40zonnet.nl > . > -- You received this message because you are subscribed to the Google Groups "Everything List" group. 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