INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky QUARKS-2008 Neutron scattering and extra short-range interactions - Neutron constraints for extra short-range interactions in the distance range of – m -Experimental neutron facility -Gravitationally bound quantum states of neutrons – micrometer range -Neutron scattering – sub-nanometer range

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Existing (usually cited) constraints for extra short-range interactions Modifications of gravity High energy physics Interaction between neutron and nucleus with the atomic mass A: mediated by a new light boson with mass M

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of neutron methods to other constraints Disadvantages of neutron experiments: -small absolute forces -statistically-limited measurements -very few people involved -… Advantages of neutron experiments: -broad wavelength range: –10 -5 m - small false systematic effects due to electric neutrality of a neutron -high-precision experiments -…

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky The distance ranges of interest Theories with 2 extra spatial dimensions Theories with 3 extra spatial dimensions

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky The neutron temperature versus the characteristic distance The neutron temperature of ~10 -8 K A factor of ~10 9 lower neutron fluxes The neutron temperature of ~10 -1 K High neutron fluxes, “easy experiments”

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Experimental neutron facility EUROforum: 7 European Research Scientific Organizations: CERN, EFDA, EMBL, ESA, ESO, ESRF, ILL ( )

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Institut Laue-Langevin (ILL), Grenoble, France World Leader in Neutron Research (Condensed matter, Magnetism, Chemistry, Biology, Crystallography, Materials, Nuclear and Particle Physics ) Experimental neutron facility

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky At the ILL: ~450 staff members, including ~70 scientists, ~20 Ph.D. students. 4 scientists in fundamental physics; 4 scientists in nuclear physics… => COLLABORATIONS 1.5 Experimental neutron facility

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Experimental neutron facility

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky 4He UCN source (a cryostat installed outside at an external beam of cold neutrons) Experimental neutron methods

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Solid-deuterium UCN source at the ILL (A piece of solid deuterium ice at the temperature of ~5K placed into the active zone of the high-flux ILL reactor) Hélium “Ejection” au réchauffement Mini D 2 He Tube SD 2 Hélium Echangeur tubulaire Experimental neutron methods

INSTITUT MAX VON LAUE - PAUL LANGEVIN Nanoparticles D 2, D 2 O, O 2, C ? d ~ 5 nm ? n T < 10 mK Neutrons can excite many degrees of freedom: Simple collision with a single nanoparticle Rotation Collective degrees of freedom (phonons, rotons) Thermalization of neutrons at ultracold nanoparticles (an extremely challenging project, involving large cryostats with ultra-low temperature of ~1 mK; with significant heat load) V.V.Nesvizhevsky Experimental neutron methods

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Mini-Workshop “Resonance transitions between the gravitationally bound quantum states of neutrons: prospects and applications (project GRANIT)” Participants ~80 Countries ~12 Europe, Asia, USA, Australia Gravitationally bound quantum states of neutrons

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Neutron above a mirror in the Earth’s gravitational field 1)Electric neutrality (usually any gravitational interaction close to surface is weaker that other interactions) 2)Long lifetime 3)Small mass 4)Energy (temperature) of UCN is extremely small and not equal to the installation temperature Gravitationally bound quantum states of neutrons the choice of neutrons Quantum state energy in the Bohr- Sommerfeld approximation :

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Frequency of perturbation, Hz Probability of transition Quantum trap Resonance transition Resonance transitions due to oscillations of: - the bottom mirror (nuclear forces); - a mass – (gravitational forces); - magnetic gradient (electro-magnetic forces). Gravitationally bound quantum states of neutrons resonance transitions between the bound states

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Constraints for spin-independent interactions MIRROR neutron New light boson of mass M New interaction between the neutron and the mirror with the range monopole-monopole coupling spin-independent Modification of the spectrum of the gravitationally bound quantum states of neutrons

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Constraints for spin-dependent interactions MIRROR neutron New light boson of mass M New interaction between the neutron and the mirror with the range monopole-dipole coupling Spin-dependant Split of every specral line into a dublet: spin-up and spin-down S.Bäßler et al, Physical Review D 75(7): (1-4) (2007); PDG-2008.

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Slow neutron scattering and extra interactions Slow neutron E< 1 eV Atom In the center of mass reference system -Values of the scattering lengths for different atoms (nuclei) are not calculated precisely from “first principles” because of complexity of the corresponding nuclei models Coherent scattering length (Fermi)  Isotropic  Energy independent  Scales as ~ A 1/3  Not isotropic  Energy dependent  Scales as ~ A Slow neutron scattering and extra interactions V.V.N., G. Pignol, and K.V. Protasov (2008). Physical Review D 77(3): (8).

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Random potential nuclear model The original model is proposed in: Peskhin, Ringo, Am. J. Phys. 39 (1971). It assumes: - Square-well potential for the neutron-nuclear interaction; - The potential well radius is equal to R 0 x A 1/3 ; - Random depth of the potential well We will seach for a contribution of an additional term ~A into the mass dependence of the measured scattering lengths

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Random potential nuclear model + extra interaction Random potential nuclear model Additional parameter

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of the forward and backward scattering  Experiments using interference method are sensitive to the forward scattering amplitude; one actually measures  Experiements using Bragg-diffraction method are sensitive to q = 10 nm -1 scattering amplitude; one actually measures Interference measurement Bragg diffraction measurement Slow neutron Atom

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of the forward and backward scattering No difference is observed for those nuclei, for which both kinds of measurement have been performed

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of the forward scattering and the total cross-section Slow neutron Atom  Experiments using optical method are sensitive to the forward scattering amplitude; one actually measures  Experiments using transmission method are sensitive to the total cross-section at 1 eV; one actually measures

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of the forward scattering and the total cross-section This idea first appeared in [Leeb and Schmiedmayer, PRL 68 (1992)] Precise measurements have been performed using both methods, in particular with lead and bismuth nuclei. However, the results were contradictory (very strong scattering of the measured values even within similar measuring methods). Therefore this work has been ignored and corresponding constraints have been never included in any analysis. The hidden difficulties: 1)Potentially large systematic effects related to nuclear structure (heavy nuclei!); 2)Electromagnetic effects have to be taken into account for neutron energy >1 eV (~1% compared to the nuclear scattering).

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Comparison of the forward scattering and the total cross-section The electromagnetic effects are overpassed in the present analysis by using the measurements of the neutron electric form-factor.

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Asymmetry of scattering of very cold neutrons (VCN) Diluted noble gaz A dedicated experiment: - Forward/Backward asymmetry of scattering of VCN at diluted noble gaz; - Statistical accuracy for the asymmetry ~10 -3 (systematic effects are smaller); - The Doppler thermal effect has to be taken into account. To get rid of the nuclear structure problem we propose to use VCN scattering at noble gas (Ar, Ks).

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Asymmetry of scattering of very cold neutrons (VCN) A dedicated experiment: - Forward/Backward asymmetry of scattering of VCN at diluted noble gaz; - Statistical accuracy for the asymmetry ~10 -3 (systematic effects are smaller); - The Doppler thermal effect has to be taken into account.

INSTITUT MAX VON LAUE - PAUL LANGEVIN V.V.Nesvizhevsky Conclusions Neutron constraints on extra interactions are several orders of magnitude better than those usually cited in the range of 1 pm - 5 nm We provide several independant strategies: neutron constraints are reliable Dedicated experiments (asymmetry of VCN scattering) can improve the constraints in the nanometer range by at least one order of magnitude.