We propose a new probe of primordial non-Gaussianities (NGs) through the observation of gravitational waves (GWs) induced by ultra-light (<math><msub><mrow><mi>M</mi></mrow><mrow><mtext>PBH</mtext></mrow></msub><mo>&lt;</mo><msup><mrow><mn>10</mn></mrow><mrow><mn>9</mn></mrow></msup><mi>g</mi></math>) primordial black holes (PBHs). Interestingly enough, the existence of primordial NG can leave imprints on the clustering properties of PBHs and the spectral shape of induced GW signals. Focusing on a scale-dependent local-type NG, we identify a distinct double-peaked GW energy spectrum that, contingent upon <math><msub><mrow><mi>M</mi></mrow><mrow><mtext>PBH</mtext></mrow></msub></math> and the abundance of PBHs at the time of formation, denoted as <math><msub><mrow><mi>Ω</mi></mrow><mrow><mi>PBH</mi><mo>,</mo><mi>f</mi></mrow></msub></math>, may fall into the frequency bands of upcoming GW observatories, including LISA, ET, SKA, and BBO. Thus, such a signal can serve as a novel portal for probing primordial NGs. Intriguingly, combining BBN bounds on the GW amplitude, we find for the first time the joint limit on the product of the effective non-linearity parameter for the primordial tri-spectrum, denoted by <math><msub><mrow><mover><mrow><mi>τ</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow><mrow><mi>NL</mi></mrow></msub></math>, and the primordial curvature perturbation power spectrum <math><msub><mrow><mi>P</mi></mrow><mrow><mi>R</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo></math>, which reads as <math><msub><mrow><mover><mrow><mi>τ</mi></mrow><mrow><mo>¯</mo></mrow></mover></mrow><mrow><mi>NL</mi></mrow></msub><msub><mrow><mi>P</mi></mrow><mrow><mi>R</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo><mo>&lt;</mo><mn>4</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>20</mn></mrow></msup><msubsup><mrow><mi>Ω</mi></mrow><mrow><mi>PBH</mi><mo>,</mo><mi>f</mi></mrow><mrow><mo>−</mo><mn>17</mn><mo>/</mo><mn>9</mn></mrow></msubsup><msup><mrow><mo>(</mo><mfrac><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>PBH</mi></mrow></msub></mrow><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>4</mn></mrow></msup><mi>g</mi></mrow></mfrac><mo>)</mo></mrow><mrow><mo>−</mo><mn>17</mn><mo>/</mo><mn>9</mn></mrow></msup></math>.

Greece

Italy

Theodoros Papanikolaou

China

Xin-Chen He

Japan

Xiao-Han Ma

Yi-Fu Cai

Chile

Emmanuel N. Saridakis

Taiwan

Misao Sasaki

New probe of non-Gaussianities with primordial black hole induced gravitational waves

We report a novel prediction from single-field inflation that even a tiny step in the inflaton potential can change our perception of primordial non-Gaussianities of the curvature perturbation. Our analysis focuses on the tail of probability distribution generated by an upward step transition between two stages of slow-roll evolution. The nontrivial background dynamics with off-attractor behavior is identified. By using a non-perturbative <italic>&#948;N</italic> analysis, we explicitly show that a highly non-Gaussian tail can be generated by a tiny upward step, even when the conventional nonlinearity parameters <math altimg='si1.svg'><msubsup><mrow><mi>f</mi></mrow><mrow><mtext>NL</mtext></mrow><mrow><mtext>local</mtext></mrow></msubsup></math>, <math altimg='si2.svg'><msubsup><mrow><mi>g</mi></mrow><mrow><mtext>NL</mtext></mrow><mrow><mtext>local</mtext></mrow></msubsup></math>, etc. remain small. With this example, we demonstrate for the first time the sensitive dependence of non-perturbative effects on the tail of probability distribution. Our scenario has an inconceivable application to primordial black holes by either significantly boosting their abundance or completely forbidding their appearance.

United Kingdom

Dong-Gang Wang

United States

Zihan Zhou

One small step for an inflaton, one giant leap for inflation: <italic>A novel non-Gaussian tail and primordial black holes</italic>

We use the spectral lag catalog of 46 short GRBs aggregated by Xiao et al. (Astrophys J Lett 924:L29, 2022), to carry out an independent search for Lorentz invariance violation (LIV). For this purpose, we use a power-law model as a function of energy for the intrinsic astrophysical induced spectral lags. The expansion history of the universe needed for constraining LIV was obtained in a non-parametric method using cosmic chronometers. We use Bayesian model comparison to determine if the aforementioned spectral lags show evidence for LIV as compared to only astrophysically induced lags. We do not find any evidence for LIV, and obtain 95% CL lower limits on the corresponding energy scale to be  $$4 \times 10^{15}$$  <math> <mrow> <mn>4</mn> <mo>×</mo> <msup> <mn>10</mn> <mn>15</mn> </msup> </mrow> </math>   GeV and  $$6.8 \times 10^{9}$$  <math> <mrow> <mn>6.8</mn> <mo>×</mo> <msup> <mn>10</mn> <mn>9</mn> </msup> </mrow> </math>   GeV for the linear and quadratic LIV models respectively. Our results obtained by using the flat  $$\Lambda $$  <math> <mi>Λ</mi> </math>  CDM model for characterizing the cosmic expansion history are consistent with those obtained using chronometers.

India

Shantanu Desai

Rajdeep Agrawal

Germany

Haveesh Singirikonda

Search for Lorentz invariance violation using Bayesian model comparison applied to Xiao et al. GRB spectral lag catalog

Considering the constraints from collider experiments and dark matter detection, we investigate the SUSY effects in the Higgs production channels e+ e− → Zh at an e+ e− collider with a center-of-mass energy above 240 GeV and γγ → h → bb̄ at a photon collider with a center-of-mass energy above 125 GeV. In the parameter space allowed by current experiments, we find that the SUSY corrections to e+ e− → Zh can reach a few percent and the production rate of γγ → h → bb̄ can be enhanced by a factor of 1.2 over the SM prediction. We also calculate the exotic Higgs production e+ e−→ Zh1 in the next-to-minimal supersymmetric model (NMSSM) (h is the SM-like Higgs, h1 is the CP-even Higgs bosons which can be much lighter than h). We find that at a 250 GeV e+ e− collider the production rates of e+ e−→ Zh1 can reach 60 fb.

Junjie Cao

South Korea

Chengcheng Han

Jie Ren

Australia

Lei Wu

Jin-Min Yang

Yang Zhang

SUSY effects in Higgs production at high energy e+ e− collidersSupported by National Natural Science Foundation of China (NNSFC)(10821504, 11222548, 11305049, 11135003), Program for New Century Excellent Talents in University, and ARC Center of Excellence for Particle Physics at Tera-scale. C. Han is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan

We consider right-handed neutrino dark matter N1 in local U(1)LÎ¼âLÏ -extended Ma model. With the light U(1)Î¼âÏ gauge boson ( mZâ²â¼O(100)Â MeV ) and small U(1)Î¼âÏ gauge coupling ( gZâ²â¼10â4â10â3 ) which can accommodate the muon (gâ2) anomaly and is still allowed by other experimental constraints, we show that we can get correct relic density of dark matter for wide range of dark matter mass ( M1â¼10â200Â GeV ), although the gauge coupling constant gZâ² is small. This is due to the fact that the annihilation cross section of dark matter pair is enhanced by M14/mZâ²4 in the processes N1N1âZâ²Zâ² or N1N1âZâ²H2 . We also consider the constraints from direct detection, collider searches.

Seungwon Baek

Dark matter and muon ( g − 2) in local U(1)Lμ−Lτ -extended Ma model