Probing the Dark Matter Direct Detection Blind Spot Scenario Using Directional Detection

Kenny Buffo Author

04/06/2021 Added

20 Plays

Description

Discussion of research as it pertains to experimental dark matter detection and theoretical extensions to probe current blind spot scenarios.

Searchable Transcript

Search:

[00:00:01.430]Hello, my name is Kenny Buffo,
[00:00:03.170]and today I'd like to talk to you
[00:00:04.460]about an ongoing research project
[00:00:06.660]that I am conducting alongside my advisor,
[00:00:09.220]Dr. Peisi Huang, a member of the High-Energy Physics group
[00:00:12.950]here at UNL.
[00:00:15.120]My research is a theoretical study of the blind spot regions
[00:00:18.750]that occur in attempting direct detection
[00:00:21.530]of dark matter and how we can resolve them.
[00:00:25.060]But what exactly is dark matter?
[00:00:29.600]Dark matter is a form of matter
[00:00:31.610]that is unlike ordinary matter
[00:00:33.190]or what physicists call baryonic matter.
[00:00:36.250]Baryonic matter is the type of matter that we see,
[00:00:38.930]feel, and experience in our everyday lives.
[00:00:42.650]Anything that's composed of atoms,
[00:00:44.370]including protons and neutrons, is baryonic matter.
[00:00:48.520]However, dark matter behaves very differently
[00:00:50.940]than the baryonic matter that we're used to.
[00:00:53.630]Evidence of its existence comes
[00:00:55.230]from calculations done on the mass distribution
[00:00:57.890]of distant galaxies.
[00:01:00.270]Astronomers found that the baryonic matter present
[00:01:02.780]in things like stars attributed to only small percentages
[00:01:06.950]of the mass needed in order to keep the stars
[00:01:09.240]from flying away outside the galaxies' reach.
[00:01:13.340]So we know that this mysterious matter
[00:01:15.220]interacts with normal matter via the gravitational force,
[00:01:19.640]but currently, it has never been directly seen.
[00:01:23.240]This is because it does not seem to interact
[00:01:25.140]with electromagnetic radiation,
[00:01:27.250]meaning it does not reflect light or absorb light,
[00:01:30.210]hence the name dark matter.
[00:01:33.680]This study of galaxies implied
[00:01:35.240]that there must be something else present in our universe,
[00:01:38.060]and a lot of it to keep everything in check.
[00:01:41.900]Current models that parameterize the Big Bang
[00:01:44.220]tell us that only about 5%
[00:01:45.620]of the universe's mass energy content is baryonic.
[00:01:50.170]This leaves a much larger portion
[00:01:51.970]to be made up of dark matter,
[00:01:53.720]and even more abundantly by dark energy.
[00:01:56.740]Dark energy is an even stranger phenomenon
[00:01:59.630]that is thought to cause the accelerating expansion
[00:02:02.330]of the universe.
[00:02:09.830]So what's the purpose of studying it?
[00:02:12.190]Why does dark matter?
[00:02:15.620]Well, particle physicists tend to make use
[00:02:18.590]of something that's referred to as the Standard Model
[00:02:21.000]when making predictions of physical events.
[00:02:23.700]The Standard Model describes three
[00:02:25.360]of the four fundamental forces, including electromagnetism,
[00:02:29.470]and the strong and weak nuclear forces.
[00:02:31.920]It currently excludes gravity.
[00:02:34.710]The Standard Model also classifies
[00:02:36.490]all the known elementary particles.
[00:02:39.100]An elementary particle is a particle
[00:02:41.440]that cannot be broken down further
[00:02:42.960]into constituent entities.
[00:02:46.530]The Standard Model lays out the rules
[00:02:48.950]that govern how these basic building blocks can interact
[00:02:52.250]and thus encompass nearly every physical process we know of.
[00:02:56.690]It is also highly accurate in its predictions,
[00:02:59.360]making it one of the most important constructions
[00:03:02.420]of 20th century physics.
[00:03:06.670]However, the Standard Model is currently incomplete.
[00:03:09.840]It does not describe dark matter,
[00:03:11.480]particularly what it's made up of
[00:03:13.480]and the rules that govern its interaction
[00:03:15.230]with other particles.
[00:03:16.840]Herein lies the motivation to devise a way
[00:03:19.220]of detecting dark matter.
[00:03:21.240]But how is it done?
[00:03:26.800]A very popular method is known as direct detection.
[00:03:29.940]These experiments aim to observe direct interactions
[00:03:32.930]between dark matter particles and ordinary matter.
[00:03:35.930]One of the most prominent ongoing experiments
[00:03:38.320]is the XENON collaboration.
[00:03:40.700]In these experiments,
[00:03:41.740]researchers place large tubes filled with xenon gas
[00:03:44.620]deep underground to filter out noise
[00:03:46.560]from unwanted detections.
[00:03:49.260]The idea is that an incoming dark matter particle
[00:03:51.770]would transfer a tiny amount of energy
[00:03:53.750]when coming into contact with the gas.
[00:03:57.330]This would cause a scintillation,
[00:03:59.230]or sudden flash of light as a property of xenon.
[00:04:03.440]Researchers can then detect these flashes
[00:04:05.660]within a tube to detect events.
[00:04:13.990]The most recent data from the XENON1T experiment
[00:04:17.260]on spin-independent dark matter is shown on the left.
[00:04:21.360]The abscissa denotes
[00:04:22.930]the possible dark matter particle mass,
[00:04:26.120]while the ordinate shows the nuclear cross-section
[00:04:29.680]of detection.
[00:04:31.120]The cross-section is directly related to the probability
[00:04:34.070]of detecting an event at that cross-section.
[00:04:37.390]This means the higher the cross-section,
[00:04:39.610]the more likely we are to see an event take place
[00:04:42.090]within the detector.
[00:04:44.870]This green band shows the current limit
[00:04:48.170]of the probed parameter space or cross-section
[00:04:52.090]that XENON has achieved.
[00:04:54.140]From this, we know that events will not take place
[00:04:57.060]above this line,
[00:05:00.000]but this still leaves this area below unprobed.
[00:05:05.500]Let us now turn our attention to the graph on the right,
[00:05:08.370]which comes from a paper published by Dr. Huang, my adviser.
[00:05:12.250]This graph describes the cross-section
[00:05:14.020]as it relates to the Higgs boson pseudoscalar mass
[00:05:17.540]under a new proposed model that extends the Standard Model.
[00:05:22.292]We see that at certain masses
[00:05:23.230]of the Higgs pseudoscalar mass,
[00:05:25.700]around 1000 giga electron volts in this graph,
[00:05:30.650]that the cross-section drops completely,
[00:05:33.140]meaning we would not find any events at this mass.
[00:05:36.360]These are referred to as blind spots,
[00:05:38.720]as experiments such as XENON
[00:05:42.034]would not be able to detect events under these conditions.
[00:05:45.680]A large portion of my research
[00:05:47.460]has been dedicated to studying the most recent data
[00:05:50.320]of spin-independent direct detection experiments
[00:05:53.870]along with the current prominent theories
[00:05:56.070]that describe the dark matter particle.
[00:06:01.997]Currently, I have been studying
[00:06:03.409]the Minimal Supersymmetric Standard Model
[00:06:06.108]and how these blind spots arise within it.
[00:06:08.955]This has required me to learn a lot
[00:06:10.492]of new theoretical physics along with multiple descriptions
[00:06:13.090]of extending the Standard Model.
[00:06:16.507]However, in order to find a way
[00:06:17.810]to probe these blind spot regions,
[00:06:20.853]I have begun using software
[00:06:21.686]to study the outcomes of these models
[00:06:24.997]and how that characterizes the dark matter particle.
[00:06:36.428]MicrOMEGAS is a software that allows
[00:06:38.735]for the study of dark matter.
[00:06:40.982]In particular, it allows me to study a specific model
[00:06:44.107]that extends the Standard Model,
[00:06:46.371]then input parameters to characterize a scenario
[00:06:49.381]within that model.
[00:06:51.891]For instance, here we see that I have set values
[00:06:54.267]for things like the Higgs mixing parameter,
[00:06:57.535]the light and heavy Higgs boson, and so on,
[00:07:00.274]all within this text file.
[00:07:03.063]Then the software does calculations
[00:07:05.290]to simulate the Minimal Supersymmetric Model, in this case.
[00:07:10.142]Finally, it outputs a lot of useful information,
[00:07:12.946]such as here we can see the breakdown of the composition
[00:07:15.651]of the dark matter particle into its constituent components.
[00:07:21.147]We can even determine if the calculated dark matter particle
[00:07:24.118]fits within the limit set by the XENON experiment.
[00:07:28.060]As seen here, it is excluded by the XENON1T experiment data
[00:07:33.836]from 2018, which means
[00:07:35.783]that this proposed dark matter particle
[00:07:38.255]would not be a good candidate
[00:07:44.947]To probe the blind spots,
[00:07:46.400]I am currently configuring the software to allow
[00:07:48.442]for directional detection as well.
[00:07:51.426]This means that the number of detected events
[00:07:54.966]will depend on the direction
[00:07:56.968]the incident dark matter particle comes from.
[00:07:59.997]My advisor and I also have plans
[00:08:01.790]to expand this to other models.
[00:08:10.087]Here's a list of my references,
[00:08:11.706]and I'd like to thank you for your time,
[00:08:13.453]and hope you enjoyed watching.

The screen size you are trying to search captions on is too small!

You can always jump over to MediaHub and check it out there.

Comments

0 Comments

Probing the Dark Matter Direct Detection Blind Spot Scenario Using Directional Detection

Description

Searchable Transcript

Comments icon comment

Related Channels

Comments